We like a good combo here at HotHardware, and we have a new one to add to the list. Right up there with peanut butter and jelly, Mario and Luigi, milk and cookies, we'd like to add dual GPUs and factory overclocks. If you are a regular reader, you probably already know we are fans of dual GPU video cards, and we have a strong affinity for factory overclocked video cards as well. And when a company combines the two, that's just fine in our book.

So, it goes without saying that we were excited to check out Diamond's overclocked Radeon HD 4870 X2 XOC graphics card (model number: 4870X2PE52GXOC). As you probably already know, the Radeon HD 4870 X2 employs two RV770 GPUs, each of which is complemented by 1GB of GDDR5 memory (for a total of 2GB frame buffer memory). The reference GPU clock speed for the 4870 X2 is 750 MHz, and the reference memory speed is 900 MHz. We are happy to report that Diamond boosted the XOC's clocks to 800 MHz and 950 MHz, respectively, making this one of the fastest 4870 X2 cards we've seen in the HotHardware labs. Speaking of the labs, we took the XOC for a spin with our benchmark suite and pitted it against a reference 4870 X2, an NVIDIA GeForce GTX 285, an NVIDIA GeForce GTX 295, and a pair of GeForce GTX 285s in SLI. Read on to see how the XOC fared in the comparison.

Since we've covered the 4870 X2 and the powerful RV770 GPU several other times here at HotHardware in various articles, we won't repeat ourselves again here. Instead, we'll invite you to check out a couple of our articles if you want to learn about the technology behind the 4870 X2 and the RV770.

• ATI Radeon HD 4850 and 4870: RV770 Has Arrived
• ATI Radeon HD 4870 X2 - AMD Back On Top

In the first article, where we discuss the launch of the Radeon HD 4850 and 4870, we go into depth on the RV770 GPU's architecture and technology. In the second article, we explain the technology that ATI used to couple two RV770 GPUs on one 4870 X2 card.

Diamond packages its 4870 X2 XOC and the included bundle in one of the simplest boxes we've ever seen for a high end video card. Usually, a graphics card box is adorned with some kind of warrior, robot or mythical creature. Sure, we jest a little bit, but we'd be lying if we didn't say that it's actually nice to see simplicity sometimes. Obviously, Diamond trusts that the card can do all the talking. The only thing that distinguishes the XOC box from the regular Diamond 4870 X2 box is the "XOC" sticker found along the top edge of the box.

In order to ensure that your sweet new graphics card arrives safely to your door, companies must design smart, protective packaging. Diamond chose to surround the 4870 X2 XOC with a nice layer of foam. Thanks to that protection, it could probably survive a relatively rough journey to its new home in your system. Along with the card, Diamond throws in a handful of practical accessories, including a Quick Start manual, a driver CD, a CrossFire bridge, a component video cable, a composite-to-S-video adapter, a DVI-to-HDMI adapter, and a DVI-to-VGA adapter. It's not a very exciting bundle, but at least the essentials are here.

Just like with the box and the bundle, Diamond kept things plain and simple with the card's design. The design is exactly the same as ATI's reference model except for the Diamond logo sticker that sits on the fan. That's not a bad thing, though, as we happen to be fans of the all-black style. When we flip the card over, you can get a good look at the two cross braces that help secure the heatsinks to the two RV770 GPUs. As is the case with all high-end video cards these days, the 4870 X2 XOC sports two dual-link DVI ports and a video out port.

Another common high-end card trait that the 4870 X2 XOC exhibits is its size -- it's long and takes up two expansion slots. In this case, though, it's more worth the extra slot since it has two GPUs. Since it is a very powerful card, it requires two connections from your system's power supply. In this case, it has to be one 6-pin and one 8-pin connector.

HotHardware's Test System Intel Core 2 Quad Powered

Let's start our round-up battle by examining the test results from Futuremark's latest 3D test suite, 3DMark Vantage. This benchmark does a good job of setting the tone of the relative performance of all the cards we are comparing in this article.

3DMark Vantage

The latest version of Futuremark's synthetic 3D gaming benchmark, 3DMark Vantage, is specifically bound to Windows Vista-based systems because it uses some advanced visual technologies that are only available with DirectX 10, which isn't available on previous versions of Windows. 3DMark Vantage isn't simply a port of 3DMark06 to DirectX 10, though. With this latest version of the benchmark, Futuremark has incorporated two new graphics tests, two new CPU tests, several new feature tests, in addition to support for the latest PC hardware. We tested the graphics cards here with 3DMark Vantage's "Extreme" preset option, which uses a resolution of 1920x1200.

When the 4870 X2 was released almost 10 months ago, it was the king of the hill, but it is hard (and unlikely) for any card to dominate for more than a few months, much less 10. The 4870 X2 lost its dominant position in January of this year when NVIDIA unleashed the GeForce GTX 295. You can see this in the 3DMark Vantage results above. Sure, the Diamond 4870 X2 and 4870 X2 XOC put up very nice scores, but they don't keep up with the GTX 295. The GTX 285 SLI setup is even more impressive. You don't get the whole picture, though, unless you consider price. A GTX 285 SLI configuration will set you back at least $650, and that's not taking into account the beefier power supply you'll need. In contrast, the GTX 295 runs about $530 or more while 4870 X2 cards can be found for less than $400. So, keep this in mind as we dive into the test results.

Unreal Tournament 3 DirectX Gaming Performance

Unreal Tournament 3

If you're a long-time PC gamer, the Unreal Tournament franchise should need no introduction. UT's fast paced action and over the top weapons have been popular for as long as Epic has been making the games. For these tests, we used the latest addition to the franchise, Unreal Tournament 3. The game doesn't have a built-in benchmarking tool, however, so we enlisted the help of FRAPS here. These tests were run at resolutions of 1920 x 1200 and 2560 x 1600 with no anti-aliasing or anisotropic filtering enabled, but with the UT3's in game graphical options set to their maximum values, with color correction and motion blur enabled.

All of the scores posted by two-GPU solutions are relatively close. The Diamond 4870 X2 XOC offers a slight advantage over the non-overclocked Diamond 4870 X2, but it doesn't quite keep up with the GTX 295 or GTX 285 SLI at 2560x1600.

Crysis v1.21 DirectX 10 Gaming Performance

Crysis

If you're at all into enthusiast computing, the highly anticipated single player, FPS smash-hit Crysis should require no introduction. Crytek's game engine visuals are easily the most impressive real-time 3D renderings we've seen on the computer screen to date. The engine employs some of the latest techniques in 3D rendering, like Parallax Occlusion Mapping, Subsurface Scattering, Motion Blur and Depth-of-Field effects, as well as some of the most impressive use of Shader technology we've seen yet. In short, for those of you that want to skip the technical jib-jab, Crysis is HOT. We ran the full game patched to v1.21 with all of the game's visual options set to 'Very High' to put a significant load on the graphics cards being tested. A custom demo recorded on the Ice level was used throughout testing.

Despite the fact that the 4870 X2 is about twice the age of the GTX 295, it does a great job keep up with the GTX 295. The overclocked 4870 X2 XOC almost matches the GTX 295 at 1920x1200 while basically tying with it at 2560x1600. Additionally, the 4870 X2 XOC gains a couple FPS over the regular 4870 X2.

Far Cry 2 DirectX 10 Gaming Performance

Far Cry 2

Like the original, Far Cry 2 is one of the more visually impressive games to be released on the PC to date. Courtesy of the Dunia game engine developed by Ubisoft, Far Cry 2's game-play is enhanced by advanced environment physics, destructible terrain, high resolution textures, complex shaders, realistic dynamic lighting, and motion-captured animations. We benchmarked the graphics cards in this article with a fully patched version of Far Cry 2, using one of the built-in demo runs recorded in the "Ranch" map. The test results shown here were run at various resolutions with 4x anti-aliasing and no anisotropic filtering enabled concurrently.

While the 4870 X2 XOC fares respectably against the GTX 295, especially at 2560x1600, we were hoping that it would best the single GTX 285 by a wider margin.

Left 4 Dead DirectX Gaming Performance

Left 4 Dead

Left 4 Dead is a cooperative, survival horror, first-person shooter that was developed by Turtle Rock Studios, which was purchased by Valve part-way into development. Like Half-Life 2, the game uses the Source engine. However, the visuals in L4D are far superior to anything seen in the Half-Life universe to date. The game pits four survivors of an apocalyptic pandemic against hordes of aggressive zombies. We tested the game at resolutions of 1920 x 1200 and 2560 x 1600 with 4x anti-aliasing and 16x anisotropic filtering enabled and all in game graphical options set to their maximum values.

The Diamond 4870 X2 and 4870 X2 XOC manage to lead the pack at 1920x1200, but then they both fall behind the other multi-GPU solutions at 2560x1600. As you can see, upping the resolution resulted in a bigger performance hit for the 4870 X2 cards than it did with the others.

Performance Summary: We were hoping for a lot from the Diamond Radeon HD 4870 X2 XOC, and for the most part, it delivered. Considering the fact that the card is based on an ATI reference design that is almost a year old, it holds its own at the highest resolutions. The Diamond 4870 X2 XOC may not always be the fastest single-card graphics solution we've tested, but it certainly is a strong performer.

We dig many dual-GPU powered cards since they allow people who don't have CrossFire or SLI capable motherboards to run pseudo-CrossFire or SLI setups. If you have to have the absolute best performance from a single card, then a two-GPU solution is your ticket, and the Diamond 4870 X2 XOC (and even the Diamond 4870 X2) are sure to please. Keep in mind, though, that if you aren't pushing at least 1920x1200 when you game, then a card like the 4870 X2 XOC is overkill in most cases. We say "most cases" because of games like Crysis and Far Cry 2. If those are the games you love, then you probably can't have too much video card power, assuming you have a CPU to balance it out of course.

While playing games with the 4870 X2 XOC, we didn't experience any problems. It wasn't all gravy, though, with the card. Something about it did not get along with our 30" HP LP3065 LCD. The card could not be set to the LP3065's native resolution of 2560x1600. As a matter of fact, it could not be set above 1280x800 when hooked up to the LP3065, but it was able to run at the native 1600x1200 resolution of our 20" LCD. It is indeed a very odd, unique and puzzling problem. We came up with a work around to complete this review, but we are still working with Diamond on the solution. We will update this article if and when we determine a resolution. Besides the odd monitor issue, we also found the noise level of the card to be a little disappointing. Like other 4870 X2 cards, the XOC is usually noticeable above the case fans, especially when the card is put under a heavy workload.

If you do not have a CrossFire or SLI motherboard, are hankering for top notch performance, and have a monitor and CPU worthy of such cards, then your two choices for FPS dominance are the GTX 295 and the 4870 X2. Although many 4870 X2's are $100+ cheaper than the GTX 295, the Diamond 4870 X2 and X2 XOC happen to be a bit closer to the $530 street price of the GTX 295. We think Diamond offers solid products, but it's hard to swallow the higher sticker prices we've seen on the web for them. We need to see Diamond's 4870 X2 and X2 XOC drop closer to the $400 range that so many other 4870 X2's are in currently in order to recommend them. If you have a CrossFire motherboard, then we recommend considering a Radeon HD 4890 CrossFire setup (maybe even with Diamond's own 4890 XOC card) instead of a 4870 X2. 

•  Good performance •  Factory overclock •  Two GPUs on one card •  DirectX 10.1 support •  CrossFireX support	•  Dual-slot card •  1-year limited warranty •  Sparse bundle •  Little louder/hotter than we'd like •  Odd issue with the LP3065 LCD •  Price a litte steeper than comparable X2's