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| Intro, Specifications and Related Info | |||||||
AMD hasn't exactly kept the product we're going to be showing you here today a secret. Once NVIDIA launched the GeForce GTX 200 series, and AMD had a look at what the cards could do first hand, AMD's marketing machine was tuned up and revved to its redline expunging the features and benefits of their upcoming GPU. Then, when the initial products in the Radeon HD 4800 series launched, AMD's plan became quite clear. The Radeon HD 4800 series didn't overwhelm NVIDIA's GTX 200 series with raw performance. In fact, the GeForce GTX 280 and 9800 GX2 were more powerful than the Radeon HD 4870. The Radeon HD 4800 series cards, however, were still excellent cards and they were offered at extremely competitive prices, which put significant pressure on NVIDA. At the time of their launch, the Radeon HD 4850 and Radeon HD 4870 were both less expensive and more powerful than the GeForce 9800 GTX and GeForce GTX 260, respectively. Since then, NVIDIA has reacted with a quick round of price cuts. While enthusiasts were contemplating the purchase of a new Radeon or GeForce, AMD then planted another seed and released some concrete details regarding the Radeon HD 4870 X2, as if to say, "Yeah, we've got you covered at the $300 price point and a new, ultra powerful behemoth is coming real soon too. Maybe you should hold onto your upgrade money for a bit?" That behemoth is the Radeon HD 4870 X2. As its name suggests, the card features two RV770 GPUs running in tandem, for what is effectively a Radeon HD 4870 CrossFire configuration on a single PCB. Other than its pair of GPUs, however, the Radeon HD 4870 X2 has a few more differentiating factors we'll need to tell you about. Read on for the full scoop...
As the above list of specifications and features show, the new Radeon HD 4870 X2 has the exact same features as the Radeon HD 4870; it just has two GPUs. Like the other members of the Radeon HD 4800 series, the Radeon HD 4870 X2 offers DX10.1 and Shader Model 4.1 support, the GPUs are manufactured on TSMC's 55nm process node, and both support ATI's CrossFireX multi-GPU technology. Perusing the sampling of articles above will lay the groundwork for much of what we'll be showing you on the pages ahead. But to reiterate some of what we explained in our initial coverage of the RV770, AMD is touting the GPU as the first solution to offer 1 TFLOPS of compute power, with higher clocked and multi-GPU offerings capable of even more.
AMD acheived this feat by increasing the population of the architecture's SP count from 320 on the older RV670 to a 800 on the RV770. AA and Z/Stencil performance were enhanced as well, and the number of texture units was increased from 16 to 40. The 800 stream processing units are grouped in a new SIMD core layout, and the texture units, ROPs, and cache have been restructured to minimize transistor count, while also increasing performance. With the RV770, AMD claims that the SPs in the GPU offer 40% more performance per square millimeter that the previous generation, and that more aggressive clock gating offers improved performance per watt as well. Likewise, the newly streamlined design of the RV770 texture units reportedly offer 70% more performance per square mm with double the texture cache bandwidth and large increases in 32- and 64-bit filter rates.
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| The Underlying Technology |
Although the cards look similar and follow a similar design philosophy, the Radeon HD 4870 X2 differs from AMD's previous dual-GPU based Radeon HD 3870 X2 in a number of ways.
The Radeon HD 4870 X2's main features and benefits are outlined on the slide above. As you can see, the cards offers up to 2.4 TFLOPS of compute power with its 750MHz core GPU clock and 1600MHz (800 x 2) stream processors. Its 2GB (1024MB per GPU) is clocked at 900MHz, which results in a 3.6Gbps GDDR5 data rate, and total memory bandwidth is 230GB/s (115GB/s x 2). With all that horsepower under the hood, the card has a max board power of 285 watts.
As the old saying goes, "But wait! There's More!" AMD has also informed us that they have a bit of a surprise in the works. A Radeon HD 4850 X2 card that utilizes less expensive GDDR3 RAM is also planned. The Radeon HD 4850 X2's primaary tech specs are outlined in the slide above. With an expected $399 MSRP, the Radeon HD 4850 could wind up being an attractive option in the current 3D graphics landscape and may put even more price pressure on NVIDIA. We hope to have the 4850 X2 in the lab in a few weeks, and will reveal all of its juicy details then. Expected availabilit is sometime in September. |
| A Closer Look At The Cards |
Upon initial inspection, the Radeon HD 4870 X2 looks much like the Radeon HD 3870 X2, just with different PCB coloring. The card features a dark, black PCB with an industrial looking image of bolts and the Radeon logo emblazoned on the fan shroud. Flip the card over, and as you probably expect, the complexity of the design shows through.
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| Our Test Systems and 3DMark06 | ||||||||||||
HOW WE CONFIGURED THE TEST SYSTEMS: We tested all of the graphics cards used in this article on either an Asus nForce 790i SLI Ultra based Striker II Extreme motherboard (NVIDIA GPUs) or an X48 based Asus P5E3 Premium (ATI GPUs) powered by a Core 2 Extreme QX6850 quad-core processor and 2GB of low-latency Corsair RAM. The first thing we did when configuring these test systems was enter their respective BIOSes and set all values to their "optimized" or "high performance" default settings. Then we manually configured the memory timings and disabled any integrated peripherals that wouldn't be put to use. The hard drive was then formatted, and Windows Vista Ultimate was installed. When the installation was complete we fully updated the OS, and installed the latest DX10 redist and various hotfixes, along with the necessary drivers and applications.
The Radeon HD 4870 X2 was predictably strong in 3DMark06. The overall score for the default benchmark doesn't tell us very much, however, as the test is CPU limited. If we tunnel down and look at the individual test results though, they better explain what's happening here.
The less taxing Shader Model 2.0 portion of the benchmark is mostly CPU bound as well. The spread in the Shader Model 3.0 / HDR test, however, is somewhat more pronounced. As you can see, the Radeon HD 4870 X2 finishes at, or very near, the top of the charts depending on the configuration tested. Based on what we see here, expect the 3DMark06 world record to be broken in the next few days by a pair of heavily overclocked Radeon HD 4870 X2 cards. The 4870 X2 CrossFire configuration put up the best overall score for a "stock" configuration we have seen to date. |
| 3DMark Vantage | ||||||
Futuremark's latest addition to the 3DMark franchise, the DX10-based 3DMark Vantage, behaved very differently than the older version of the benchmark. In this test, the deltas separating the different configurations are huge. As you can see, the Radeon HD 4870 X2 manhandles any other single graphics card in the list. And when running in tandem, a pair of Radeon HD 4870 X2 cards bests almost every other configuration, save for a trio of GeForce GTX 280 cards.
As we look deeper into the 3DMark Vantage results, the individual GPU tests tell essentially the same story. Although the framerates are different, the overall trends in the data are the same. The Radeon HD 4870 X2 outpaces every other single card configuration and only the GeForce GTX 280 3-way SLI setup is faster. |
| Half Life 2: Episode 2 | ||||||
Our custom Half Life 2: Episode 2 benchmark was no match for the Radeon HD 4870 X2. As the results show, the new Radeon HD 4870 X2 is clearly the fastest single graphics card in this game and pairing up two cards in a CrossFire X configuration only serves to increase performance. At the highest resolution, the 4870 X2 is bested by a couple of NVIDIA SLI configurations, but when running a pair of Radeon HD 4870 X2s in CrossFire, they can't be touched--no other setup came close when everything was maxed out. |
| Unreal Tournament 3 | ||||||
Unreal Tournament 3 is largely CPU bound, even at a resolution 1920x1200. With the game running at 2560x1600 though (the blue bars in the graph), things spread out a bit more. At that resolution, the Radeon HD 4870 X2 is the fastest of all the single-card configurations and it hangs with a GTX 260 SLI rig. In a dual-card CrossFireX configuration, a pair of 4870 X2 cards also puts up the best score bar none, but the GeForce GTX 200 series SLI setups are right there with it, finishing only a couple of frames per second behind. |
| Enemy Territory: Quake Wars | ||||||
Our custom Enemy Territory:Quake Wars benchmark tells essentially the same story as the previous games tests. The new Radeon HD 4870 X2 put up the best scores for any single graphics card configuration. The game did scale with two Radeon HD 4870 X2 cards running in CrossFireX mode as well, but not enough to fend off NVIDIA's flagship offerings. In this game, the GeForce GTX 280 SLI configuration takes the top spot at 1920x1200, and the 3-way GTX 280 SLI setup takes the lead at 2560x1600. |
| Crysis v1.2 | ||||||
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| SD and HD Video Performance | ||||
We also did some testing of the Radeon HD 4870 X2's UVD video processing engine, in terms of both image quality and CPU utilization with some HQV and H.264 playback tests.
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 Cyberlink's PowerDVD HD, with hardware acceleration for AMD AVIVO HD and NVIDIA PureVideo HD extensions enabled.
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| Total System Power Consumption | ||||
We'd like to cover a few final data points before bringing this article to a close. Throughout all of our benchmarking and testing, we monitored how much power our test systems were consuming using a power meter. Our goal was to give you all an idea as to how much power each configuration used while idling and under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power being drawn by the motherboards alone.
As you can see, the Radeon HD 4870 X2 isn't going to end up in any "green" PCs. When either idling or running under a heavy graphics workload, the Radeon HD 4870 X2 consumed more power than another single graphics card, and sometimes more than two single-GPU based graphics cards. The 4-GPU, Radeon HD 4870 X2 CrossFireX configuration also consumed more power than any other graphics card configuration by a large margin. |
| Our Summary and Conclusion | ||||
Performance Summary: Throughout our entire battery of tests, the new Radeon HD 4870 X2 proved to be a top performer, whether running in a single-card configuration or in a dual-card, four-GPU, CrossFireX configuration. In the games and applications we tested, the Radeon HD 4870 X2 outperformed every other single graphics card, including the GeForce GTX 280. Generally speaking, the 4870 X2 was on-par with or marginally faster than a Radeon HD 4870 CrossFire setup and somewhat faster than a GeForce GTX 260 SLI configuration in most benchmarks, although the GTX 260 SLI rig did catch up with it a couple of times. Depending on how well the Radeon HD 4870 X2 CrossFireX configuration scaled, it too was one of the fastest multi-GPU configurations available, but a pair or trio of GeForce GTX 280 cards were faster in a few instances.
Make no mistake, the new Radeon HD 4870 X2 marks ATI's return to the top of the 3D graphics food chain. It took a few years, but through steady improvements in multi-GPU software support, and a new strategy regarding the design and manufacture of high-end graphics cards that utilizes two mid-sized chips in lieu of a single monolithic one, AMD was able to produce a graphics card capable of outpacing the best NVIDIA currently has to offer. As we stated in our conclusion when we first took a look at AMD's previous two-GPU flagship, the Radeon HD 3870 X2, because the Radeon HD 4870 X2 is essentially “CrossFire on a card”, the X2’s performance is ultimately determined by how well the card’s drivers scale in a particular game. If a new game hits store shelves and the drivers don’t recognize its executable, the $549 Radeon HD 4870 X2 will perform much like a single-GPU Radeon HD 4870 that is approximately half the price. On many occasions since the launch of the Radeon HD 3870 X2, AMD has assured us their software team will continually be working to try to minimize this situation, but it quite possibly could be an issue at some point in time no matter how hard they work, unless a universally compatible multi-GPU rendering technique is devised. This is something you must be aware of if you’re contemplating the purchase of Radeon HD 4870 X2. Expect Radeon HD 4870 X2 cards to be available immediately for about $549. At that price, the Radeon HD 4870 X2 is certainly not for everyone and it is the most expensive consumer level graphics card on the market. But prices in the graphics card space have been on downward spiral for weeks and we suspect this card won't remain at that price for long, even if NVIDIA doesn't release something new to steal some of ATI's thunder. A GTX 280, for example, may not perform as well as the 4870 X2 overall, but it is currently about $100-$150 less expensive (after rebates) and users won't have to worry about multi-GPU scaling issues. Although the Radeon HD 4870 X2 is an all-around faster card, the price difference and the benefits of the GeForce GTX 280's single-GPU design still make it an attractive option for hardcore enthusiasts in our opinion. In the end though, the Radeon HD 4870 X2 simply rocks. We wish it didn't run quite as hot and that its cooler was a bit quieter, but those are things ATI's partners will likely address. Welcome back to ultra high-end AMD. It's obvious you have worked hard, and your efforts have paid off. The Radeon HD 4870 X2 is a 3D graphics tour de force.
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