 |
 |
 |
||
|
|
||||
 |
|
|
| Introduction and Related Information | ||||||
In January of this year, at the Consumer Electronics Show in Las Vegas, NVIDIA and Dell jointly unveiled an ultra high-end gaming system equipped with a pair of specialized graphics adapters that were each powered by a pair of GeForce 7800 GTX GPUs and 1GB of memory. The final configuration consisted of two "cards", four GPUs, and a total of 2GB of graphics memory. NVIDIA dubbed the technology "Quad-SLI", and gave Dell an exclusive on the technology for a short period of time. At the time NVIDIA didn't announce any plans to bring Quad-SLI to retail, but we all knew the day would eventually come. While that day is not today (technically), NVIDIA is laying the foundation for do-it-yourself Quad-SLI with the release of the new GeForce 7950 GX2. The GeForce 7950 GX2 is a refinement of the technologies employed in the first dual-GPU cards used in the original Quad-SLI design. The 7950 GX2 features newer GPUs and revised PCB designs that not only make the cards physically smaller, but more power efficient and ultimately more compatible with existing platforms. Though Quad-SLI may or may not be ready for prime time in the mainstream just yet, the GeForce 7950 GX2 is being targeted by NVIDIA as the fastest single graphics adapter on earth currently -- a single graphics adapter with dual GPUs.
The GeForce 7950 GX2 is equipped with a pair of G71 GPUs. We've covered the features and specifications of the G71 in a couple of previous articles, so we won't go into detail again here. For a more comprehensive look at the main features of the GeForce 7 series, and some more details regarding NVIDIA's multi-GPU SLI platform as a whole, we recommend taking a look at a few of our recent articles...
We know that's a lot of reading, but the information and performance data in the articles listed above will give you all of the background and architectural details necessary to fully understand the new product being announced today. If you're unclear about anything on the proceeding pages, look back to these articles for more detail. |
| Enter the GeForce 7950 GX2 | ||||
Although the GeForce 7950 GX2 is being officially announced by NVIDIA today, we tested a sample from XFX in full retail trim. Unlike many of XFX's other products, the XFX GeForce 7950 GX2 570M XXX ships in a standard rectangular box and not one of the company's signature "X" shaped boxes. Many of the 7950 GX2's main features are listed right on package, including support for HDCP.
XFX includes a good assortment of software and accessories with their GeForce 7950 GX2 570M XXX. Along with the GX2 itself, we found a handful of manuals that detail the installation and features of the product, a pair of DVI-to-DB15 adapters, a dual-Molex to 6-pin PCI Express power adapter, an S-Video cable, and an HD component output adapter. In addition to these items, XFX includes a couple of CDs as well. One disc contains the drivers necessary to install the GX2, and the other is a full version of Tomb Raider: Legend. It was very nice to see an up-to-date A-List title included with high-end product like this. Tomb Raider: Legend recently received a 90% rating in PC Gamer.
If you've seen the 7800 GX2 and 7900 GX2 boards used in the first Quad-SLI systems, you'll immediately notice that the GeForce 7950 GX2 is significantly smaller. In fact, the 7950 is about the same size as a 7900 GTX at approximately 9" long. The 7950 GX2 also has only one SLI connector at the top, as opposed to the two found on earlier 7800 / 7900 GX2s. The GeForce 7950 GX2 is equipped with two GeForce 7950 GPUs, each coupled to 512MB of fast GDDR3 memory, for a grand total of 1GB of frame buffer memory. The 7950 GPU is based on the same G71 design used on the 7900 GTX; it's just clocked a bit lower. NVIDIA's reference 7950 GX2 specifications call for a 500MHz GPU clock with 600MHz (1.2GHz DDR) memory. The XFX model pictured here, however, is clocked much higher at 570MHz / 775MHz (1.55GHz DDR). Each GeForce 7950 GX2 is built from a pair of PCBs linked together through a proprietary interface. If you look at the fourth picture above, you can actually see the connector that resides between the two PCBs. The two GPUs and on-board memory all get their own slim coolers. The GeForce 7950 GX2 requires only a single 6-pin PCI Express power feed, and cards features a pair of dual-link DVI outputs along with an S-Video / HD component output. To use the GX2 in multi-monitor mode, however, multi-GPU mode must be disabled in the drivers, just like SLI. |
| More on the Hardware |
To give you all an idea as to how the GeForce 7950 GX2's specifications compare to the previous flagship GeForce 7900 GTX and the 7900 GT, we've got a simple chart (courtesy of NVIDIA) that shows how the products differ.
As you can see, many of the GeForce 7950 GX2's specifications are doubled, like the pixel and vertex shaders and ROPs, because the GX2 features a pair of GPUs. Due to differences in clock speed, however, the GeForce 7950 GX2 doesn't have double the horsepower of a GeForce 7900 GTX, but it does have major advantages in a couple of categories, most notably pixel and texel fill rate and vertices per second.
The GeForce 7950 GX2 has another feature not found on any of NVIDIA's single-GPU card as well. The GX2 is equipped with an NVIDIA designed PCI Express switch that allows each GPU to communicate over a single PCI Express x16 link. On the 7950GX2 the switch connects to the system over all 16 lanes, but to each GPU with 8 lanes. The reason NVIDIA went with 8 lanes of connectivity to each GPU, was to provide for shorter PCB board design while still delivering good performance. Turning off 16 lanes in the NVIDIA 48 lane PCIe switch also provides a bit of power savings. On the 7900 GX2, NVIDIA routes 16 lanes to each GPU from the switch, which is one of the reasons the 7900 GX2 is so much longer. We should also note that the GX2 does not require a full PCI Express x16 electrical connection to function. When NVIDIA eventually supports Quad-SLI in the DIY segment, a pair of 7950 GX2s will function in older nForce 4 SLI based motherboards. Because the traffic coming in is already 8 lanes (from the chipset splitting a 16 lane PCIe connection into two 8 lane connections going to each PEG slot), the switch will interface with the 8 lane connection to the chipset, and just pass 8 lanes worth of traffic to each addressed GPU as needed. So, Quad-SLI will eventually be supported on all SLI capable chipsets like the NF5, NF4 SLIx16, and standard NF4 SLI. Although the NVIDIA PCI Express switch is compliant with the standard PCI Express specification, the system BIOS of some motherboards may not properly recognize the 7950 GX2 right away. Without a properly configured system BIOS, the motherboard could fail to post or may not operate reliably. NVIDIA informed us that they have worked closely with motherboard manufacturers to have their system BIOSes updated to support the GX2. Please refer to this site for a list of known compatible motherboards and the proper BIOS versions that have been tested by NVIDIA. Please note the list on that site is not inclusive of all compatible motherboards, but rather reflects motherboards that have already been tested and qualified by NVIDIA. This list will be updated over time as more new motherboards are tested. And also notice the GX2 works on many platforms, including the 975X Express and CrossFire Xpress 3200. |
| Forceware Rel. 90 | ||||
A couple of weeks ago, NVIDIA quietly released a new set of Forceware drivers on nZone.com that feature a brand new control panel interface. Obviously, The new Forceware Rel. 90 drivers also support the GeForce 7950 GX2, but Rel. 90 is more than just a simple driver update. NVIDIA has done a lot of things with Forceware Rel. 90 that are noteworthy.
NVIDIA's new control panel is a complete departure from their older design. Forceware Rel. 90 was designed with Microsoft's upcoming Windows Vista in mind, and as such it features a new look that blends well with Vista. But the new interface is right at home with Windows XP too. NVIDIA also wanted to tie in the look of the Forceware control panel with their nForce drivers and nTune system tweaking utility as well. As you can see, each main section of the drivers has its own clearly labeled icon in the main interface. NVIDIA's goal was to make navigating the control panel more user friendly, and to have more room to incorporate new features into the drivers. When user's click on any of the main icons, they are presented with a list of options to adjust various settings.
In the 3D Settings category, all of the options that used to previously reside on one overcrowded screen are now broken out into their own sections. Image quality options now feature a real-time preview that shows how a particular setting will affect image quality, and all 3D settings are clearly listed. We should also note that virtually every option has a description and a typical usage scenario listed at the bottom of the main window. And in the left column, recent and related tasks are listed along with a complete help section. These changes and additions make navigating the control panel significantly easier. |
| Forceware Rel. 90 (Continued) | ||||
There are a multitude of screens and options available in the new Forceware Rel. 90 drivers, too many to show them all here. But we do have some more screen captures from two of the main categories below -- Display and Video & Television. The images below were captured with the drivers configured for Advanced users. There is a Basic view available as well. And if you prefer the older interface that's still an option too.
The main display options in Rel. 90 are laid out in a much more intuitive manner, and like the 3D image quality settings, display options that affect image quality are previewed on an image on the right.
We also found the Video & Television related control panel menus to be easier to navigate and more user friendly. Although you can't see it in the sceenshots above because the overlay isn't captured, there is a real-time preview on the right as well. With Forceware Rel. 90, NVIDIA has incorporated a couple of new options that you may not have seen before. With Rel. 90, the PureVideo engine has been updated with Edge Enhancement and Noise Reduction algorithms. And user's can tweak these algorithms manually. Rel. 90 also enhanced PureVideo's inverse telecine and de-interlacing algorithms to detect and correct more film cadences, as you'll see later on in our HQV results. |
| More Rel. 90 and The GeoForms | ||||
NVIDIA spent considerable resources engineering the new Forceware Release 90 drive suite. The new control panel design simply didn't come about from an arbitrary decision to make a change. NVIDIA actually built their own Software Usability Lab complete with state-of-the-art digital video equipment to aid them in the design.
User reactions were monitored in the usability lab and the new Rel. 90 control panel was molded based on those reactions. NVIDIA also used Microsoft and human interface research in the design, they interviewed NVIDIA and OEM support staff for suggestions, and also took user comments in many open forums into consideration. The end result is a completely new control panel with a larger emphasis on usability, that's much easier to navigate and understand. The Forceware Release 90 drivers give enthusiasts more control over their hardware, and give novices an easier to use interface. If you haven't already installed these new drivers on your own systems, we urge you give them a shot. According to NVIDIA, 88% of users preferred the new interface in "blind taste tests" that took place in the usability lab.
Whenever NVIDIA unveils a new flagship graphics card, they usually release a new demo to exploit the card's new features and performance capabilities. To coincide with the launch of the new GeForce 7950 GX2, NVIDIA is introducing a new demo dubbed GeoForms. In this new demo, the GeoForms change their shape to the beat of music. The GeoForms can also change their subatomic organization, quickly morphing into almost any material, be it glass, metal, water, wax, putty, brushed metal, marble, or jade. The materials can range from opaque to translucent, polished smooth to rough as sand, and from plain to porous and veined. The GeoForms demo uses many advanced rendering techniques, including HDR with anti-aliasing (using a proprietary technique), HDR Motion Blur, HDR Lens Flare, Real-time "Depth Peeling" Refraction, and Sub-Surface Light Scattering. |
| Our Test Systems and 3DMark06 | ||||||||||||||
HOW WE CONFIGURED THE TEST SYSTEMS: We tested the NVIDIA based cards on an Asus A8N32-SLI nForce 4 SLIX16 chipset based motherboard. The ATI powered cards, however, were tested on an A8R32-MVP motherboard based on the CrossFire Xpress 3200 chipset. Both systems used the same AMD Athlon 64 FX-60 dual-core processor and 2GB of low-latency Corsair XMS RAM, though. The first thing we did when configuring these test systems was enter each BIOS and loaded their "High Performance Defaults." The hard drive was then formatted, and Windows XP Professional with SP2 was installed. When the installation was complete, we installed the latest chipset drivers available, installed all of the other drivers necessary for the rest of our components, and removed Windows Messenger from the system. Auto-Updating and System Restore were also disabled, the hard drive was defragmented, and a 1024MB permanent page file was created on the same partition as the Windows installation. Lastly, we set Windows XP's Visual Effects to "best performance," installed all of the benchmarking software, and ran the tests.
To make the graphs in this article a bit easier to read, we've grouped the dual-card and single-card configurations into two sections. The top of the graphs are all technically single-card configurations, although one could argue that the 7950 is two cards. The bottom of the graphs are made up of dual-card configurations. Also note that we've tested the GeForce 7950 GX2 at both NVIDIA's reference clock speeds and XFX's shipping clock speeds, which are significantly higher. As you can see, the new GeForce 7950 GX2 is one heck of a performer, regardless of whether or not it's clocked at NVIDIA's reference specs in XFX's "pre-overclocked" state. The single 7900 GTX and Radeon 1900 XTX cards are simply left in the dust according to 3DMark06. The SLI and CrossFire rigs fare much better, as well they should considering they cost hundreds of dollars more than a single 7950 GX2.
If we break down the results into their individual components, we see that all of the NVIDIA powered cards perform very well in 3DMark06's shader model 2.0 tests, edging out their ATI powered counterparts by a fair amount.
In the HDR and shader model 3.0 tests, however, ATI's Radeon X1900 XTX is a fair bit faster than the 7900 GTX. The 7950 GX2's two GPU configuration is untouchable in this test though without running a high-end SLI or CrossFire rig. Overall, the new 7950 GX2 is roughly 40% faster than a single 7900 GTX in 3DMark06 and it trails a 7900 GTX SLI setup by about 17% depending on its GPU and memory clock speeds. |
| Splinter Cell: Chaos Theory v1.05 | ||||||
If you're a regular HotHardware.Com reader, you may be thrown off by the graphs you see here and on the remaining pages. For this article, we've eliminated all of the 'standard' benchmarks that don't feature any anti-aliasing or anisotropic filtering. Quite frankly, if you're buying a high-end graphics card to game without AA and aniso, you're wasting your money. You don't need a $500+ graphics card to get high frame-rates with anti-aliasing and anisotropic filtering disabled. We've tested all of the cards in this article at two of the most popular resolutions according to a recent reader poll, with 4X anti-aliasing and 8X or 16X anisotropic filtering enabled throughout. And a little later on, we'll throw in some ultra-high 1920x1200 resolution tests as well. The graphs are broken up by resolution, not by the level of graphics detail as in previous articles. The new GeForce 7950 GX2 blew right past the GeForce 7900 GTX and Radeon X1900 XTX in the Splinter Cell benchmark, regardless of the resolution. Whether or not the GX2 was clocked at NVIDIA's reference specs or XFX's higher clock speeds, it had a huge advantage over any other single card setup. The dual-card CrossFire and SLI rigs were faster, however. |
| FarCry v1.33 | ||||||
All of the graphics cards we tested performed very well in our custom FarCry benchmark. What's interesting to note is that the GeForce 7950 GX2 and the GeForce 7900 GTX SLI and the Radeon X1900 XT CrossFire rigs were all essentially CPU bound at both resolutions. Only a couple of frames per second separate all of the dual-GPU configurations here. The single-GPU configurations, however, trailed by significant margins once we raised the resolution to 1600x1200. The increased fillrate, memory bandwidth, and shader performance offered by ATI's CrossFire and NVIDIA's SLI / GX2 dual-GPU technologies have a large impact on performance in graphically intense situations. |
| Half Life 2 | ||||||
Even though this game is still rather impressive visually, Half Life 2 simply doesn't tax any of today's high-end graphics cards. ATI's Radeon X1900 XTX, whether running in a single-card configuration or in a dual-card CrossFire setup put up the best scores here, technically speaking, but all of the rigs were CPU bound. The slight differences in performance shown in the graph above can likely be attributed to game engine optimizations and reduced CPU overhead in ATI's drivers more than anything else. |
| F.E.A.R. v1.05 | ||||||
The GeForce 7950 GX2's dominant performance continued in the F.E.A.R. benchmark. The 7950 GX2 was upwards of 20 frames per second faster than any other single card at both resolutions when clocked at NVIDIA's reference specs, and sometimes up to 30 frames per second faster thanks to XFX's higher clocks. The GeForce 7900 GTX SLI rig was the fastest overall, but this time around the CrossFire rig fell victim to the 7950 at 1600x1200. CrossFire's relatively poor scaling in this game at higher resolutions allowed the GX2 to blow right past it, especially the XFX card, which smoked the CrossFire setup by 14 frames per second, which equates to roughly 21%. |
| Quake 4 v1.2 | ||||||
The GeForce 7950 GX2 tore right through our custom Quake 4 benchmark. It absolutely crushed all of the single card configurations, and the XFX version even hung right up there with a GeForce 7900 GTX SLI rig. The reference GeForce 7950 GX2 performed just a bit lower than the X1900 XT CrossFire rig, but the XFX GeForce 7950 GX2, with its higher GPU and memory clocks, outpaced the CrossFire setup by significant margins at both resolutions we tested. |
| 1920x1200 - 3DMark06 and Splinter Cell | ||||||||
We continued our testing of the new GeForce 7950 GX2 with some high resolution, widescreen benchmarks using Dell's gorgeous 2405FPW 24" LCD. We re-ran a handful of tests at a resolution of 1920x1200 too see how each card fared when pressed in a more taxing situation than our traditional set of benchmarks.
3DMark06 told us basically the same story as it did earlier. The GeForce 7950 GX2 when clocked at both NVIDIA's reference specifications or in XFX's pre-overclocked state simply manhandles the GeForce 7900 GTX and Radeon X1900 XTX. The GeForce 7900 GTX and Radeon X1900 XT CrossFire rigs were the best performers overall though, outscoring the GX2 by about 600 to 1400 points.
All of the card we tested were capable of producing playable framerates in the Splinter Cell: Chaos Theory benchmark, but there is no doubt that a dual-GPU configuration offers much better performance at ultra-high resolutions. The GeForce 7950 GX2 couldn't catch the SLI or CrossFire rigs, but it easily outpaced the 7900 GTX and Radeon X1900 XTX, regardless of its clock speed configuration. The higher-clocked XFX GeForce 7950 GX2 was over 30 frames per second faster than the X1900 XTX here. Imagine what two of them running in a QuadSLI configuration can do. |
| 1920x1200 - HL2 and Quake 4 | ||||||||
We continued our testing of the new GeForce 7950 GX2 with another round of high-resolutions tests using our custom Half Life 2 and Quake 4 benchmarks.
Even at an ultra high resolution of 1920x1200 with 4X anti-aliasing and 16X anisotropic filtering enabled, Half Life 2 was still almost completely CPU bound. In this batch of tests, the Radeon X1900 XTX and X1900 XT CrossFire rigs once again finished at the top of the charts, but the NVIDIA powered cards were not very far behind.
Quake 4 showed a much larger performance delta at 1920x1200 than any of the other benchmarks we ran. Here, the GeForce 7950 GX2 doubled the performance of an X1900 XTX when clocked at XFX's specifications, and beat the XTX by almost 30 frames per second when clocked at NVIDIA's reference specs. The XFX card was faster than an X1900 XT CrossFire configuration as well, but the GeForce 7900 GTX rig was the top dog by about 5 frames per second. |
| PureVideo Updates and Performance | |||||||||||||
For our next round of tests we took another look at Digital Video processing performance between the two competing core GPU architectures, "PureVideo" technology at work for NVIDIA and "AVIVO" driving ATI.
To characterize CPU utilization when playing back WMV HD content, we used the Performance Monitor built into Windows XP. Using the data provided by Windows Performance Monitor, we created a log file that sampled the percent of CPU utilization every second, while playing back the 1080p version of the "The Living Sea" video available for download on Microsoft's WMVHD site. The CPU utilization data was then imported into Excel to create the graph below. The graph shows the CPU utilization for a GeForce 7950 GX2 and a Radeon X1900 XTX using Windows Media Player 10, patched using the DXVA updates posted on Microsoft's web site (Updates Available Here).
The GeForce 7950 GX2 and Radeon X1900 XTX were roughly on par with one another, CPU utilization-wise, when playing High-Def content in Windows Media Player 10. The 7950 GX2 put up slightly lower utilization numbers versus the Radeon X1900 XTX, but the difference was less than 2%. We should also note that depending on the particular video being played, CPU utilization can change to favor either architecture.
Next up, we have a relatively new addition to the HotHardware testing arsenal, the HQV DVD video benchmark from Silicon Optics. HQV is comprised of a sampling of SD video clips and test patterns that have been specifically designed to evaluate a variety of interlaced video signal processing tasks, including decoding, de-interlacing, motion correction, noise reduction, film cadence detection, and detail enhancement. As each clip is played, the viewer is required to "score" the image based on a predetermined set of criteria. The numbers listed below are the sum of the scores for each section. We played the HQV DVD using the latest version of Intervideo's WinDVD 7 Platinum Suite, with hardware acceleration and PureVideo extensions enabled.
As we mentioned in our GeForce 7900 GTX evaluation a few months back, both NVIDIA and ATI have been working on new drivers that would drastically improve their performance in the HQV video benchmark. It seems that NVIDIA has come on very strong with their PureVideo support in the new Forceware Rel. 90 drivers, and ATI continues to improve their score in this "benchmark" with each driver release as well. Both companies have improved their score over time thanks to enhanced noise reduction, image sharpening, and inverse telecine algorithms. We've given both architectures the same score of 113, but must provide some explanation because ATI and NVIDIA do not produce the same results. We initially gave a score of 108 to ATI here, but after scrutinizing the results in the Detail test, it was clear ATI deserved a higher score. ATI does not give users the ability to tweak their edge enhancement algorithm via the Catalyst Control Panel, and their technique doesn't produce as dramatic a change as NVIDIA's in its current state, but there is a definite improvement in image quality in this particular test. Our Noise Reduction results are also somewhat deceptive. In the Noise Reduction tests, ATI does a very good job of eliminating noise from the various scenes, and some scenes are near perfect. NVIDIA does a good job as well, but depending on what level is set in the driver, NVIDIA's technique could produce some noticeable artifacts. So, even though we give both architectures a 5 in these two tests, ATI currently does a better job. We hesitate to give either architecture a 10 in these tests because whenever there is a color transition, some noise is still clearly visible. This confusion is ultimately the result of how a score should be determined in HQV. To score a perfect 10 in the Detail and Noise Reduction tests, little to no noise must be visible in the various scenes. To score a 5 there must be some improvement, and to score 0 the scene must remain unchanged. According to HQV's scoring guidelines, we would not give either architecture a perfect score of 10, but they both improve the scenes, which is why they both scored 5s. There is a bit of subjectivity in these tests though, please keep that in mind. We tend to be conservative with our scoring in HQV, but in a "best case scenario", ATI would score 123 here. Another thing we should bring to your attention is that NVIDIA no longer requires a separate purchase to take full advantage of PureVideo. Whereas users were previously required to purchase a copy of NVIDIA's PureVideo decoder to enjoy all of the benefits of PureVideo, now many popular third-party players like WinDVD and PowerDVD can take full advantage of PureVideo's features. Great move NVIDIA. |
| Overclocking the GeForce 7950 GX2 | ||||
As we neared the end of our testing, we spent a little time overclocking the new GeForce 7950 GX2 using the clock frequency slider available within NVIDIA's Forceware drivers, after enabling the "Coolbits" registry tweak. To find the card's peak core and memory frequencies, we slowly raised their respective sliders until we begun to see visual artifacts on-screen while running a game or benchmark. Please note that the GX2's GPU have to be overclocked in tandem, and not individually. The peak clock speed attainable by the "slower" of the two GPUs will determine the maximum overclock.
Considering the fact that XFX's GeForce 7950 GX2, or more specifically the 570M XXX Edition that we've tested here, is pre-overclocked at the factory, we weren't expecting it to have much more headroom left for overclocking. Just to reiterate, NVIDIA's reference specifications call for 500MHz GPU clock speeds with 600MHz memory and XFX configures their card with its GPUs clocked at 570MHz and its memory at 775MHz. By overclocking the card, however, we were able to take it up to 585MHz for the GPUs and 812MHz for the memory. That was only an increase of 15MHz for the GPUs over XFX's "out-of-box" specifications, but the memory shot up by an additional 37MHz. While we had the card overclocked, we re-ran a couple of benchmarks and gained a few points in 3DMark06 and a couple of frames per second in our custom Quake 4 test. The increases weren't enough to catch a GeForce 7900 GTX SLI configuration, but that hardly matters when the GeForce 7950 GX2's performance is as high as it is. |
| Power Consumption and Noise | ||||
We have a few final data points to cover before bringing this article to a close. Throughout all of our benchmarking, we monitored how much power our NVIDIA based test system was consuming using a power meter, and also took some notes regarding its noise output. Our goal was to give you all an idea as to how much power each configuration used and to explain how loud the configurations were under load. Please keep in mind that we were testing total system power consumption here, not just the power being drawn by the video cards alone.
The GeForce 7950 GX2's power consumption, regardless of whether or not its clocked at NVIDIA's or XFX's specifications, falls somewhere in between a single GeForce 7900 GTX and a 7900 GTX SLI configuration. While idling at the Windows desktop the GX2 system peaked at 195w, and while running with a full 3D workload it peaked at 332w, 44w lower than a pair of 7900 GTX running in SLI mode. While we were testing the new GX2, we also positioned a sound level meter a few inches away from the card to see how much noise it's dual coolers were generating. In the worst case scenario, with the fans on both coolers running at full speed and the meter placed directly above the heatsinks, the GX2 registered 68db. If we backed away a few more inches though, the sound of the CPU cooler and PSU drowned out the GX2. Subjectively speaking, we would not consider the GX2 loud by any means. The fans emit more of a whine than a 7900 GTX, but we weren't distracted by the sound at any point in our testing. Having a pair of PCBs sandwiched together, however, does make the 7950 run a but on the warm side. We sampled temperatures using an infrared thermometer at various points on the GX2 and found that the heatsink surface on the front GPU hit 49oC, while the other heatsink in the middle of the PCBs was at 62oC at the same time. We also took a reading from the back of the PCB behind the GPU and found that the board hit a peak temperature of 67oC. That's a huge difference in temperature between the front and middle-mounted heatsinks. This situation could pose a problem in a case that's not well ventilated. |
| Our Summary & Conclusion | ||||
Performance Summary: The new GeForce 7950 GX2 is undoubtedly the fastest, most powerful graphics adapter available. In every test we ran, with the exception of a couple that were CPU bound, the GeForce 7950 GX2 handily outpaced a GeForce 7900 GTX and a Radeon X1900 XTX. The 7950 GX2 was also a bit faster than a pair of Radeon X1900 XTs running in CrossFire mode in a few of our F.E.A.R. and Quake 4 tests, but it couldn't quite catch a pair of GeForce 7900 GTXs running in SLI mode. The GX2 performs much like a pair of GeForce 7900 GTs running in SLI mode, but the GX2's larger frame buffer will give it an edge over a pair of 7900 GTs clock-for-clock in many situations.
We were very impressed by the GeForce 7950 GX2, like many of the products NVIDIA has released as of late. We hesitate to call the 7950 GX2 a "single card" solution, because quite frankly it is a pair of cards bolted together that happen to use a single slot. But the GeForce 7950 GX2 is a single graphics adapter no matter how you slice it. Although it's powered by dual-GPUs and leverages NVIDIA's SLI technology, it's compatible with multiple platforms and will work with most motherboards that feature a PEG slot, provided the motherboard's BIOS has been flashed to support the GX2's proprietary PCI Express switch. And on top of the broad compatibility, the GeForce 7950 GX2 is an excellent performer. NVIDIA will still be limiting Quad-SLI support to its own nForce platform. For now though, Quad-SLI is not supported in the DIY segment and will only available from select system builders. This will likely be changing in the coming weeks, however. And there is nothing in the drivers to prevent users from slapping two GX2s into a single system now. It's just not officially supported yet. While we're talking about the drivers, we also have to give NVIDIA praise for the Forceware Rel. 90 suite. The new Vista-like interface took some getting used to, but after a couple of hours exploring we preferred the updated look of the new interface hands down. We also like the fact that NVIDIA has exposed all of PureVideo's advanced features without the need to purchase a separate decoder. The new noise reduction, edge enhancement, and inverse telecine algorithms incorporated into the PureVideo engine also worked well, and gave NVIDIA an edge over the competition in the HQV benchmark and in our CPU utilization test. The GeForce 7950 GX2 will be available immediately from multiple outlets for approximately $599 to $649. Higher clocked cards like the XFX GeForce 7950 GX2 570M XXX we looked at here will likely be priced at the upper end of the spectrum, however. That's not exactly cheap, but considering the GX2 features a pair of G71 GPUs and 1GB of fast GDDR3 memory, that price is a bit more justifiable in a sea of $500, single-GPU, 512MB graphics cards. With its extreme performance, new driver suite with enhanced PureVideo capabilities, and broad platform compatibility, the GeForce 7950 GX2 is sure to get many hardcore enthusiasts worked up into a frenzy. We can't wait to get a second one in the lab for some Quad-SLI testing. As it stands now, a single GX2, and especially a higher clocked model like XFX's 570M XXX Edition is a very compelling upgrade to any single graphics card currently available. We're giving the XFX GeForce 7950 GX2 570M XXX Edition a strong 9 on the Heat Meter and a rare Editor's Choice award.
|
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
;)
