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ATI Radeon X1650 XT with Native CrossFire
Date: Oct 30, 2006
Author: Marco Chiappetta
Introduction, Specifications, and Related Info

About two weeks ago, ATI launched the Radeon X1950 Pro, a new mainstream graphics card with a host of new features. This graphics card was equipped with a single-slot cooler, a relatively low-power GPU that was manufactured on TSMC's 80nm fabrication process, and in a first for ATI, native CrossFire support.  Native CrossFire support meant there would be no more confusion over CrossFire Master and Slave cards, and the clunky external dongle previously associated with CrossFire was no longer a necessity.

In our evaluation of the X1950 Pro, we praised ATI for producing a high-performance, affordable, single-slot solution, with a more elegant approach to multi-GPU technology than their previous offerings. Although availability of the Radeon X1950 Pro is just now starting to ramp up and we've only been able to locate a single card that comes close to ATI's MSRP (which even they were unable to hit for some reason), it's clear that the X1950 Pro is a solid product in the mainstream market segment.

Today, ATI is adding yet another member to the Radeon X1K family of products, the Radeon X1650 XT. While its name suggests the X1650 XT is nothing more than a higher clocked variation on the barely 2-month old Radeon X1650 Pro, that's actually not the case.  The Radeon X1650 XT is based on a new GPU, formerly code-named RV560, that is much more powerful than anything else in the X16x0 family. Take a look...

ATI Radeon X1650 XT
Features & Specifications
- 80nm fabrication process
- 24 pixel shader processors
- 8 vertex shader processors
- Up to 256-bit 8-channel memory interface
- Native PCI Express x16 bus interface

Ring Bus Memory Controller
- Internal ring bus for memory reads
- Fully associative texture, color, and Z/stencil cache designs
- Hierarchical Z-buffer with Early Z test
- Lossless Z Compression (up to 48:1)
- Fast Z-Buffer Clear
- Optimized for performance at high display resolutions, including widescreen HDTV resolutions

Ultra-Threaded Shader Engine
- Support for Microsoft DirectX 9.0 Shader Model 3.0 programmable vertex and pixel shaders in hardware
- Full speed 128-bit floating point processing for all shader operations
- Up to 512 simultaneous pixel threads
- Dedicated branch execution units for high performance dynamic branching and flow control
- Dedicated texture address units for improved efficiency
- 3Dc+ texture compression o High quality 4:1 compression for normal maps and two channel data formats
- High quality 2:1 compression for luminance maps and single-channel data formats
- Complete feature set also supported in OpenGL 2.0

Advanced Image Quality Features
- 64-bit floating point HDR rendering supported throughout the pipeline
o Includes support for blending and multi-sample anti-aliasing
- 32-bit integer HDR (10:10:10:2) format supported throughout the pipeline
o Includes support for blending and multi-sample anti-aliasing
- 2x/4x/6x Anti-Aliasing modes
o Multi-sample algorithm with gamma correction, programmable sparse sample
patterns, and centroid sampling
o New Adaptive Anti-Aliasing feature with Performance and Quality modes
o Temporal Anti-Aliasing mode
o Lossless Color Compression (up to 6:1) at all resolutions, including widescreen HDTV resolutions
- 2x/4x/8x/16x Anisotropic Filtering modes
o Up to 128-tap texture filtering
o Adaptive algorithm with Performance and Quality options
- High resolution texture support (up to 4k x 4k)
Avivo Video and Display Platform
- High performance programmable video processor
o Accelerated MPEG-2, MPEG-4, DivX, WMV9, VC-1, and H.264 decoding and
o DXVA support
o De-blocking and noise reduction filtering
o Motion compensation, IDCT, DCT and color space conversion
o Vector adaptive per-pixel de-interlacing
o 3:2 pulldown (frame rate conversion)
- Seamless integration of pixel shaders with video in real time
- HDR tone mapping acceleration
o Maps any input format to 10 bit per channel output
- Flexible display support
o Dual integrated dual-link DVI transmitters
o Dual integrated 10 bit per channel 400 MHz DACs
o 16 bit per channel floating point HDR and 10 bit per channel DVI output
o Programmable piecewise linear gamma correction, color correction, and color space
conversion (10 bits per color)
o Complete, independent color controls and video overlays for each display
o High quality pre- and post-scaling engines, with underscan support for all outputs
o Content-adaptive de-flicker filtering for interlaced displays
o Xilleon TV encoder for high quality analog output
o YPrPb component output for direct drive of HDTV displays
o Spatial/temporal dithering enables 10-bit color quality on 8-bit and 6-bit displays
o Fast, glitch-free mode switching
o VGA mode support on all outputs
o Drive two displays simultaneously with independent resolutions and refresh rates
- Compatible with ATI TV/Video encoder products, including Theater 550

- Multi-GPU Technology
- Four modes of operation:
o Alternate Frame Rendering (maximum performance)
o Supertiling (optimal load-balancing)
o Scissor (compatibility)
o Super AA 8x/10x/12x/14x (maximum image quality)

We have a plethora of information related to today's launch available on our site that will help you get familiar with the GPU architecture and key features employed on the new Radeon X1650 XT cards we'll be showcasing here. The Radeon X1650 XT has a number of features in common with some other members of the Radeon X1K family of products. And we've detailed the features of the Radeon Xpress 3200 chipset and ATI's CrossFire multi-GPU technology in a few past articles as well.

If you haven't already done so, we recommend scanning through our CrossFire Multi-GPU technology preview, the CrossFire Xpress 3200 chipset evaluation, the X1K family review, and the Radeon X1950 Pro with Native CrossFire articles. In those four pieces, we cover the vast majority of the features offered by the Radeon X1650 XT. There is quite a bit of background information in these articles that lays the foundation for what we're going to showcase here today.

The New Radeon X1650 XT

At first glance, the new Radeon X1650 XT looks much like the Radeon X1600 XT that launched in early October of last year. With the exceptions of the similar shaped cooler and a red PCB, physically the cards are very different.


ATI Radeon X1650 XT with Native CrossFire

As we've already mentioned on the previous page, the Radeon X1650 XT is based on the GPU formerly codenamed RV560. This GPU, which is clocked at 575MHz, is built on TSMC's 80nm node and features 24 pixel shader processors, 8 vertex shaders and 8 texture units. The board is outfitted with 256MB of GDDR3 RAM running at 675MHz (1.35GHz DDR), which the GPU communicates with via a 128-bit interface.  This configuration gives the Radeon X1650 XT a maximum of 21.6GB/s of memory bandwidth. 

The Radeon X1650 XT also features a pair of dual-link DVI outputs, HDCP support, HD/TV output, and a couple of edge connectors along the top which enable its built-in Native CrossFire support. ATI essentially incorporated the compositing engine that used to reside on CrossFire Master card right into the GPU die. As far as functionality is concerned, the CrossFire on the Radeon X1650 XT works just like it did on older members of the Radeon X1K family, save for the dongle. To run X1650 XT cards in a CrossFire configuration, all you have to do is connect them via a pair of internal ribbon cables, similar to NVIDIA's SLI bridge. Unlike the NVIDIA platform though, these ribbon cables will be bundled with the video cards and not the motherboards, because there are a plethora of Intel 975 and P965 boards already available that are CrossFire compatible, that don't ship with the appropriate connector cables. ATI will be including one CrossFire connector with each card moving forward.

The cooler used on the X1650 XT is low-profile and all copper. It did a fine job keeping the card cool throughout our testing, as we did not experience any instability whatsoever until we overclocked the card well out of spec. We did find the fan to be somewhat audible, however.  When it spins up to its maximum speed, the X1650 XT's fan emitted a bit of whine, that was audible over our test system's CPU and PSU fans.  When spun-down, however, the fans are nice and quiet, which is how they operated most of the time.  As for the Radeon X1650 XT's power requirements, they are relatively low.  In fact, the card does not feature a supplemental 6-Pin PCI Express power connection, which means the 75W supplied by a typical PEG slot is adequate.

As you would expect, given the card's proposed $149 price point, ATI is positioning the Radeon X1650 XT against NVIDIA's GeForce 7600 GT.  To give you an idea as to how the X1650 XT stacks up against some of its main competition, we've put together a quick chart highlighting some important features. As you can see, at least according to their specifications, the Radeon X1650 XT compares favorably to NVIDIA's current offerings. But let's see what happens when we actually plug them in and put them through some benchmarks.

  Radeon X1650 XT Radeon X1650 Pro GeForce 7600 GT GeForce 7900 GS
Core Frequency 574MHz 600MHz 560MHz 450MHz
Memory Frequency 675MHz 700MHz 700MHz 660MHz
Vertex Shaders 8 5 5 7
Pixel Shaders 24 12 12 20
Pixel Fill Rate 4.5 Billions/s 2.4 Billions/s 4.5 Billions/s 7.2 Billions/s
MSRP ~$149* ~$130 ~$150 ~$199

* Street prices are likely to be higher than $149 until partners have wide availability

Our Test Systems and 3DMark06

HOW WE CONFIGURED THE TEST SYSTEMS: We tested the NVIDIA based cards used in this article 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 RAM. The first thing we did when configuring these test systems was enter each BIOS and loaded their "High Performance Defaults."  The hard drives were then formatted, and Windows XP Pro 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 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.

The HotHardware Test Systems
AMD Athlon 64 FX Powered

Processor -

Motherboard -

Video Cards -

Memory -

Audio -

Hard Driv
e -


Hardware Used:
AMD Athlon 64 FX-60 (2.6GHz x 2)

Asus A8N32-SLI
nForce4 SLIX16 chipset

Asus A8R32-MVP
ATI CrossFire Xpress 3200

GeForce 7600 GT (x2)

GeForce 7950 GT (x2)
GeForce 7900 GT
GeForce 7900 GS
Radeon X1650 XT (x2)
Radeon X1650 Pro
Radeon X1950 Pro (x2)

2048MB Corsair XMS PC3200 RAM

Integrated on board

Western Digital "Raptor"

74GB - 10,000RPM - SATA

Operating System -
Chipset Drivers -
DirectX -

Video Drivers

Synthetic (DX) -
DirectX -
DirectX -
DirectX -
OpenGL -
Relevant Software:
Windows XP Professional SP2
nForce Drivers v6.86
DirectX 9.0c (August Redist.)

NVIDIA Forceware v91.45

ATI Catalyst v6.8/6.9B

Benchmarks Used:
3DMark06 v1.0.2
FarCry v1.33*
F.E.A.R. v1.07
Half Life 2: Episode 1*

* - Custom Test (HH Exclusive demo)
Performance Comparisons with 3DMark06 v1.0.2
Details: http://www.futuremark.com/products/3dmark06/

3DMark06 is the latest addition to the 3DMark franchise. This version differs from 3Dmark05 in a number of ways, and now includes not only Shader Model 2.0 tests, but Shader Model 3.0 and HDR tests as well. Some of the assets from 3DMark05 have been re-used, but the scenes are now rendered with much more geometric detail and the shader complexity is vastly increased as well. Max shader length in 3DMark05 was 96 instructions, while 3DMark06 ups the number of instructions to 512. 3DMark06 also employs much more lighting, and there is extensive use of soft shadows. With 3DMark06, Futuremark has also updated how the final score is tabulated. In this latest version of the benchmark, SM 2.0 and HDR / SM3.0 tests are weighted and the CPU score is factored into the final tally as well.

The Radeon X1650 XT just misses the mark set by the GeForce 7600 GT in 3DMark06's default test.  Whether running in single-card or CrossFire modes, the X1650 XT is just a hair slower than the GeForce 7600 GT, or 7600 GT SLI configurations overall.

The reason the Radeon X1650 XT trailed the 7600 GT overall becomes evident when we look at the individual results. In the Shader Model 2.0 test, the GeForce 7600 GT was about 120 points faster than the X1650 XT in single-card mode.  And when running in an SLI configuration, the 7600 GT's lead jumps to approximately 220 points.

The Radeon X1650 XT actually pulls ahead of the GeForce 7600 GT in both single and dual-card configurations in 3DMark06's Shader Model 3 / HDR test.  Its margin of victory, however, is quite small, which is why it was not able to overtake the GeForce 7600 GT in the overall score.

Half Life 2: Episode 1

Performance Comparisons with Half Life 2: Episode 1
Details: http://www.half-life2.com/

Half Life 2: Episode 1
Thanks to the dedication of hardcore PC gamers and a huge mod-community, the original Half-Life became one of the most successful first person shooters of all time.  So, when Valve announced Half-Life 2 was close to completion, gamers the world over sat in eager anticipation. Upon its release, HL2 was universally lauded, and the sequel won an array of "Game of the Year" awards. Armed with the latest episodic update to HL2, Episode 1, we benchmarked the game with a long, custom-recorded timedemo that takes us through both outdoor and indoor environments. These tests were run at resolutions of 1,280 x 1,024 and 1,600 x 1,200 with 4X anti-aliasing and 16X anisotropic filtering enabled concurrently, and with color correction and HDR rendering enabled in the game engine as well.


In single card mode, the Radeon X1650 XT and GeForce 7600 GT perform right on par with each other at 1280x1024, but the new Radeon jumps out to a significant 20% lead once the resolution is cranked up to 1600x1200.

Unfortunately, CrossFire doesn't scale quite as well as SLI here.  In dual-card CrossFire mode, the Radeon X1650 XT cards outpace the 7600 GT cards by about 10% at the lower resolution, but that lead dwindles to almost nothing once the resolution is raised to 1600x1200.

Far Cry v1.33

Performance Comparisons with FarCry v1.33
Details: http://www.farcry.ubi.com/

If you've been on top of the gaming scene for some time, you probably know that FarCry was one of the most visually impressive games to be released on the PC in the last few years.  Courtesy of its proprietary engine, dubbed "CryEngine" by its developers, FarCry's game-play is enhanced by Polybump mapping, advanced environment physics, destructible terrain, dynamic lighting, motion-captured animation, and surround sound. Before titles such as Half-Life 2 and Doom 3 hit the scene, FarCry gave us a taste of what was to come in next-generation 3D gaming on the PC. We benchmarked the graphics cards in this article with a fully patched version of FarCry using a custom-recorded demo run taken in the "Catacombs" area checkpoint. The tests were run at various resolutions with 4X AA and 16X aniso enabled concurrently.

The new Radeon X1650 XT performed relatively well in our custom FarCry benchmark. Here, the X1650 XT was about 10% faster than the GeForce 7600 GT at both resolutions when running in single-card mode. Things took a turn for the worse once we enabled CrossFire though.  In CrossFire mode, a pair of Radeon X1650 XT cards loses out to a GeForce 7600 GT SLI configuration by about 5% at 1280x1024. But with the resolution turned up to 1600x1200, the Radeon X1650 XT cards come back strong and squeaks out a slight victory over the GeForces.

F.E.A.R. v1.07

Performance Comparisons with F.E.A.R
More Info: http://www.whatisfear.com/us/

One of the most highly anticipated titles of 2005 was Monolith's paranormal thriller F.E.A.R. Taking a look at the game's minimum system requirements, we see that you will need at least a 1.7GHz Pentium 4 with 512MB of system memory and a 64MB graphics card in the Radeon 9000 or GeForce4 Ti-classes or better, to adequately run the game. Using the full retail release of the game patched to v1.07, we put the graphics cards in this article through their paces to see how they fared with a popular title. Here, all graphics settings within the game were set to their maximum values, but with soft shadows disabled (Soft shadows and anti-aliasing do not work together currently). Benchmark runs were then completed at resolutions of 1,280x960 and 1,600x1,200, with anti-aliasing and anisotropic filtering enabled.


In single-card mode, the Radeon X1650 XT pulled off another slight victory over the GeForce 7600 GT, besting NVIDIA's current mid-range offering by a couple of frames per second at both resolution.  F.E.A.R. just doesn't want to cooperate with CrossFire though.  At both resolutions, the GeForce 7600 GT cards' performance running in SLI mode scales by over 90%.  Conversely, the Radeon X1650 XT's performance scales by only 10% to 50% in CrossFire mode, so they trail the GeForce cards by a significant margin here.

Prey Performance

Performance Comparisons with Prey
Details: http://www.prey.com/

After many years of development, Take-Two Interactive recently released the highly anticipated game Prey. Prey is based upon an updated and modified version of the Doom 3 engine, and as such performance characteristics between the two titles are very similar.  Like Doom 3, Prey is also an OpenGL game that uses extremely high-detailed textures and a plethora of dynamic lighting and shadows.  But unlike Doom3, Prey features a fare share of outdoor environments as well.  We ran these Prey benchmarks using a custom recorded timedemo with the game set to its "High-Quality" graphics mode, at resolutions of 1,280 x 1,024 and 1,600 x 1,200 with 4X AA and 16X anisotropic filtering enabled simultaneously.


Things could not have been much closer in our custom Prey benchmark. With the cards running in a single-GPU configuration, a fraction of a frame per second separates the Radeon X1650 XT from the GeForce 7600 GT, with the Radeon just slightly out in front at both resolutions. The same holds true in the multi-GPU configurations as well. In fact, at 1280x1024, the Radeon X1650 XT CrossFire and GeForce 7600 GT SLI configurations put up the exact same score of 68.1 FPS, and only .2 frames per second separated them at 1600x1200.

Overclocking the Radeon X1650 XT

For our next set of performance metrics, we spent a little time overclocking the Radeon X1650 XT using the clock frequency sliders available within ATI's drivers, under the "Overdrive" tab.

Overclocking the Radeon X1650 XT
(Fast 3D Video Cards) + Overclocking = Even Faster Cards

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, or until our test system was no longer stable.

Radeon X1650 XT - Overclocked Speeds: 601MHz Core / 759MHz (1.57GHz DDR) Memory
Radeon X16950 XT - Default Clock Speeds: 574MHz Core / 672MHz (1.34GHz DDR) Memory


Radeon X1650 XT - Overclocked Speeds: 601MHz Core / 759MHz (1.57GHz DDR) Memory
Radeon X16950 XT - Default Clock Speeds: 574MHz Core / 672MHz (1.34GHz DDR) Memory

When all was said and done, we were able to take the Radeon X1650 XT up from its default GPU core and memory clock speeds of 574MHz / 672MHz, to 601MHz / 759MHz, increases of 27MHz and 87MHz or 4.7% and 13%, respectively.  With the card overclocked, we re-ran a couple of benchmarks to see what kind of performance had been gained.  As you can see, F.E.A.R.'s framerate went up by 2 FPS and Prey's went up by 2.4 FPS.  Nothing earth-shattering, but you won't hear us complain about free performance gains very often.

Our Summary and Conclusion

Performance Summary: The new Radeon X1650 XT performed on-par or slightly better than a GeForce 7600 GT throughout our entire battery of tests. A pair of Radeon X1650 XT cards running in CrossFire mode, however, traded victories with a pair of GeForce 7600 GT cards running in SLI mode and occasionally lost by a wide margin, like in the F.E.A.R. benchmark. The X1650 XT was also clearly more powerful than the X1650 Pro, but the more expensive Radeon X1950 Pro and GeForce 7900 GS and GT cards were quite a bit faster than the new X1650 XT.

ATI's new Radeon X1650 XT is a solid cost competitive offering, given a few caveats. If the card hits store shelves at its proposed price point of $149, it fills a nice gap in ATI's mid-range product offerings and competes favorably with NVIDIA's similarly priced products. The card performs well, doesn't require supplemental power, it takes up only a single slot, and it supports Native CrossFire. All good things.

Unfortunately, representatives from ATI (or should we say AMD now?) have informed us that board partners are not likely to hit MSRP, at least not initially; a recurring theme it seems with ATI these days.  NVIDIA clearly has a better handle right now on executing for volume production ramps and getting costs in line quickly.  For example, you can now finally find a Radeon X1950 Pro from Sapphire for the product's target MSRP of $199 but it took a few weeks to get there.  Also, unfortunately Radeon X1650 XT cards won't be available for a couple of more weeks (November 13).  At $150, we'd have no problem recommending the Radeon X1650 XT to those of you in the market for a card in that price range.  If they creep up to the $170 to $180 range though, we'd say save your pennies and pick up a GeForce 7900 GS or Radeon X1950 Pro.  Of course, as always, it's up to ATI to make the former option a reality.  Let's hope they do.

  • Good Performance
  • Native CrossFire
  • Single-Slot
  • Low-Power
  • Decent Overclocker
  • Late to the game
  • DX10 Looming

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