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ATI's Radeon X1800 CrossFire Edition graphics card

Dual Radeons put on a Christmas light show
— 8:00 AM on December 12, 2005

ATI'S FORTUNES HAVE BEEN dented a little bit by delays to its CrossFire dual-graphics solution and its Radeon X1000-series graphics chips, but red team has been scrambling to catch up. The company has brought to market most of the pieces of a brand-new, top-to-bottom lineup of products with a rapid-fire succession of product launches. After a few sputters, most Radeon X1000 series graphics cards are now available, as are CrossFire motherboards and video cards. ATI still needs to deliver a few missing pieces in order to catch up with its rival NVIDIA, and that's what we have gathered here today.

If you're longing to see a $1200 Radeon graphics subsystem under the Christmas three this year, you will need a Radeon X1800 CrossFire Edition graphics card. This magical device will allow you to sync up with a regular Radeon X1800 XT or XL graphics card for nearly double the rendering power of a single card. This new CrossFire card also sweeps away some of the limitations of the first-generation CrossFire hardware introduced just a couple of months ago, allowing mega-high-res gaming, among other things.

Now, we know the Radeon X1800 XT isn't quite as bone-jarringly fast as NVIDIA's new GeForce 7800 GTX 512, but it's still a fire-breathing monster. Running two X1800 XTs together in CrossFire is a good way to strain your neck, singe your hair, or at least develop a very serious addiction to F.E.A.R.—but we're willing to take that chance for you, our loyal readers. Keep reading to see how ATI puts on a Christmas light show, Radeon style.

Welcome your new master... card
Let's start at the beginning and say that if all of this talk about "CrossFire" leaves you confounded, you probably ought to go read our initial review of ATI's CrossFire solution. CrossFire involves a motherboard, a special video card, a regular Radeon, an external dongle cable connecting the two cards, and a graphics driver to animate all of this hardware. If you're not familiar with this CrossFire contraption, you probably won't understand the significance of a new CrossFire Edition card.

Our ATI Radeon X1800 CrossFire test rig

The Radeon X1800 CrossFire Edition

The card itself is very much like the Radeon X1800 XT that we reviewed not too long ago. It looks pretty much the same, and it packs a 625MHz R520 GPU and 512MB of GDDR3 memory, just like the X1800 XT. Oddly, though, our Radeon X1800 CrossFire review unit came with memory running at 720MHz, or 1440MHz effectively through the clock-doubling powers of DDR memory. The regular Radeon X1800 XT runs its RAM at 750MHz, or effectively 1.5GHz.

The minor discrepancy here is a little baffling, although it should have a fairly minimal impact on performance. When paired up with the Radeon X1800 XT, the CrossFire card should run its RAM at the lower speed while the XT maintains the higher RAM clock. CrossFire configs can run in these somewhat asymmetrical conditions with different GPU and memory clocks, although overall performance is usually gated by the slower of the two cards. Rendering every other frame (or a portion of each frame) on a slower graphics card tends to hold the faster card back.

Speaking of which, the Radeon X1800 CrossFire Edition can also work in concert with the Radeon X1800 XL, a lower end card with 500MHz GPU clock and only 256MB of memory clocked at 500MHz (or 1GHz effective). In fact, ATI has no plans to release a slower, less expensive CrossFire card to match up more exactly with the Radeon X1800 XL. If you want to do the dually thing with your X1800 XL, you're gonna have to pony up for the full, six-hundred-dollar Radeon X1800 CrossFire experience. Then, once you plop the CrossFire card into your system next to the Radeon X1800 XL, the CrossFire card will proceed to deactivate half of its 512MB memory in order to match up with the XL's RAM size. (The Radeon X1800 CrossFire will maintain its higher GPU and memory clock speeds, though.)

Transitioning in and out of CrossFire mode will be a little more inconvenient, too, since the system must be rebooted in order for the CrossFire card to deactivate half of its RAM. A chicken must also be sacrificed during the reboot. No reboot or ritual offering is required with the Radeon X1800 XT.