Why You Can Trust CNET ATI Radeon HD 3870 X2 review: ATI Radeon HD 3870 X2
ATI Radeon HD 3870 X2
AMD's new ATI Radeon HD 3870 X2 graphics card delivers on its promise of best-in-class 3D performance at a similar price to the comparable card from Nvidia. If we were buying a new 3D card or a new gaming desktop, the $450 Radeon HD 3870 X2 is the card we would look for, at least today. We would feel much more strongly about this recommendation if ATI had the drivers to back up this card's hardware prowess, especially because, by the time ATI does polish the drivers, Nvidia may have made new product introductions. Our overall suggestion is to wait for ATI to update its driver software and to see what else might be on the horizon before laying out for this, or any other, high-end 3D card.
The Good
The Bad
The Bottom Line
What makes the Radeon HD 3870 X2 different is that it uses two Radeon HD 3870 graphics chips on a single card. This is similar in design to Nvidia's GeForce 7950 GX2 from a few years ago. The Radeon HD 3870 X2 relies on ATI's CrossFire multicard technology to make the chips work in tandem, making this single card as powerful, or as limited, as the Crossfire support in individual PC games.
| ATI Radeon HD 3870 X2 (R680) | Nvidia GeForce 8800 GTX (G80) | |
| Lowest current price | $449 | $449 |
| Manufacturing process | 55nm | 90nm |
| Transistors | 666 million (per chip) | 681 million |
| Core clock | 825MHz | 575MHz |
| Stream processors | 320 (per chip) | 128 |
| Memory | 512MB (per chip) | 768MB |
| Memory speed (data rate) | 900MHz (1.8GHz) | 900MHz (1.8GHz) |
| Memory Interface | 256-bit | 384-bit |
On Unreal Tournament 3, for example, you can see that the Radeon 3870 X2 beat the GeForce 8800 GTX by a good 8 frames per second on average. Like this title, many PC games will benefit from Crossfire and the two-chip design, allowing you to play them at very high resolutions and image-quality settings.
(Longer bars indicate better performance)
 | 1,600 x 1,200, 4x anti-aliasing, 8x anisotropic filtering, high quality |
On Call of Duty 4, though, the Radeon HD 3870 X2 didn't get any faster than a single Radeon HD 3870, and both results are slower than a single GeForce 8800 GTX. We suspect this has to do with AMD's Crossfire drivers and the way they apportion the processing of the smoke effects on the screen during GameSpot's testing. GameSpot tried testing on another Call of Duty level with less smoke and saw a 60 percent performance improvement. The slowdown appears to be specific to Call of Duty 4, so you shouldn't worry too much about particle effects in other games killing your frame rate, but the issue here illustrate that, like SLI, Crossfire is susceptible to quirks, and is not always a perfect solution.
(Longer bars indicate better performance)
| 1,600 x 1,200, maximum quality |
Crysis, of course, is the big daddy of current PC games. It has DirectX 9 and DirectX 10 modes, and no single graphics card has been able to deliver acceptable frame rates in it at high settings. As the scores for the Radeon HD 3870 X2 show, it appears that even two chips can't get the job done. It's faster than the GeForce 8800 GTX and a single Radeon HD 3870, so the 3870 X2 does in fact benefit from its two chips in Crysis. Unfortunately, that's not enough to push it into the promised land of 60 frames per second in either DirectX 9 and Windows XP or in Windows Vista and Direct X 10 with an updated driver.
What's interesting is that even though Crysis is often held up as the poster child for DirectX 10 gaming, DirectX 10 itself does not appear to be the chief factor in why this game is so challenging for current hardware. We suspect game developers will continue to add DirectX 10 features to their games slowly, so while the DirectX 10 performance outlook games remains elusive, as Crysis shows, DirectX 9 can still challenge even brand new 3D hardware. The solution for now is to dial down the image quality and the resolution, at which point you should be able to achieve a more playable frame rate.
(Longer bars indicate better performance)
| 1,600 x 1,200, high quality |
(Longer bars indicate better performance)
| 1,600 x 1,200, high quality |
On top of performance, the Radeon HD 3870 X2 brings with it a few advanced features, some that matter, some that don't. Probably the most important is its PCI Express 2.0 support. You can still use the Radeon HD 3870 X2 in current generation PCI Express 1.0 slots, but with added PCI E 2.0 capability, this will open the card up for forthcoming motherboards with these next-gen slots and their wider data bandwidth. Like DirectX 10, PCI E 2.0 is a forward-looking feature, but especially if you pair up two X2 cards in a CrossfireX configuration (ATI's 3 three and four-3D chip technology, available as soon as driver and motherboard support allows), all that 3D processing capability may very well need a fatter data pipe to feed it enough information. Time will tell.
Like its other 3000-series 3D cards, AMD also touts the 3870 X2's DirectX 10.1 support. Do not buy this card for that reason alone. No games use DirectX 10 yet to full effect. DirectX 10.1 (which adds only a few graphical tweaks beyond vanilla DX10) is even farther away. Having that capability now only ensures that some day when DirectX 10.1 games arrive, this card will technically support those features. But by that time both ATI and Nvidia will likely have released newer cards in this price range. Adding DirectX 10.1 support is harmless, and we always welcome future-proofing, but it won't show its value until likely 2009.
Otherwise, the Radeon HD 3870 X2 comes with most of the common features we expect from 3D cards these days. It has full HDCP-compatibility, so you can use it in systems that have a protected Blu-ray or HD DVD optical drive. You can also use the Radeon HD 3870 X2 to power two displays, including two 30-inch LCDs, each at 2,560x1,600.
Installing the Radeon HD 3870 X2 doesn't require anything beyond a power connection, a PCI Express graphics slot, and room for a double-wide 3D card. You'll need a typical six-pin power connection to your PC's power supply. The card also has a separate eight-pin connector, which you'll need to use if you intend to overclock it. AMD makes no official power supply recommendation for a single 3870 X2, although its Web site does suggest at least a 550-watt power supply for two standalone Radeon HD 3870 cards. We suspect you wouldn't want to go any lower than 450 watts or so for a single 3870 X2, especially if you paired it with a quad-core CPU.
The only other thing we'll add is that the 3870 X2 is one of the heaviest 3D cards we've encountered. It weights a hefty 2.25 pounds. Its weight won't affect DIY hobbyists that much, just be sure to use those bracket screws. System builders who have to ship systems to customers will have a harder time. We suspect the use of card retaining brackets will become more popular this year.
Thanks, as always, to James Yu and Sarju Shah at GameSpot for their benchmarking expertise.