ATI MultiGPU Done Right: The Radeon X1800 CrossFire Edition
by Derek Wilson on December 20, 2005 9:00 AM EST- Posted in
- GPUs
The New Improved CrossFire
With the X1800 series of CrossFire cards, we will finally be able to test resolutions above 1600x1200. When it comes to multiGPU solutions, the more flexibility the user gets, the better. It is difficult to justify dropping over a thousand dollars on a setup that has limitations, and the removal of the single-link TMDS receivers definitely makes this version of CrossFire a more viable solution than its first incarnation in the X800 series.
The addition of dual-link TMDS receivers on the master card marks the biggest upgrade we see on the X1800 version of CrossFire. With a new dongle connector, and the improved bandwidth of dual-link DVI, ATI has given their customers what they need to power huge resolutions. We will still be limited in performance on a game by game basis, as alternate frame rendering (AFR) is still the most efficient (and most restrictive) multiGPU mode in which to work. While ATI's Scissor and SuperTiling modes offer some flexibility and the extended SuperAA modes offer an alternate way to add value to games (enhancing quality rather than performance), there are some caveats we will mention in our performance analysis (in particular with Black and White 2).
The basic features of CrossFire haven't changed from the initial design. For a refresher on CrossFire, check out our previous articles on the subject. Aside from the TMDS upgrades, ATI has refreshed their compositing engine with a larger FPGA from Xilinx. This allows ATI to composite the larger images possible with dual-link DVI input. Most of the rest of the CrossFire hardware is either unchanged or only slightly altered. From a board layout stand point, it would certainly make more sense if ATI were to build GPU to GPU communication into their parts as NVIDIA has done with SLI. Incorporating a silicon version of their compositing engine onto their GPUs would save board space and could improve performance even more.
From a high level, the X1800 CrossFire edition can be paired with a regular X1800 XT or an X1800 XL. There isn't a cheaper CrossFire card for the cheaper X1800 XL, and in order to get CrossFire setup and running with the X1800 XL, half of the RAM on the card needs to be disabled. In order to disable the RAM, the system needs to be rebooted, but in other cases CrossFire can be enabled and disabled without rebooting. While adding a CrossFire card to one's existing X1800 XL setup will definitely increase performance, it is ends up delivering even less for your money than when pairing it with an X1800 XT. The price tag is already a bit hefty, and we expect that most people who want this card will be those who need the absolute maximum performance possible. The value of CrossFire as an upgrade won't really be worth it unless the price of the X1800 CrossFire card comes down quite a bit.
With the X1800 series of CrossFire cards, we will finally be able to test resolutions above 1600x1200. When it comes to multiGPU solutions, the more flexibility the user gets, the better. It is difficult to justify dropping over a thousand dollars on a setup that has limitations, and the removal of the single-link TMDS receivers definitely makes this version of CrossFire a more viable solution than its first incarnation in the X800 series.
The addition of dual-link TMDS receivers on the master card marks the biggest upgrade we see on the X1800 version of CrossFire. With a new dongle connector, and the improved bandwidth of dual-link DVI, ATI has given their customers what they need to power huge resolutions. We will still be limited in performance on a game by game basis, as alternate frame rendering (AFR) is still the most efficient (and most restrictive) multiGPU mode in which to work. While ATI's Scissor and SuperTiling modes offer some flexibility and the extended SuperAA modes offer an alternate way to add value to games (enhancing quality rather than performance), there are some caveats we will mention in our performance analysis (in particular with Black and White 2).
The basic features of CrossFire haven't changed from the initial design. For a refresher on CrossFire, check out our previous articles on the subject. Aside from the TMDS upgrades, ATI has refreshed their compositing engine with a larger FPGA from Xilinx. This allows ATI to composite the larger images possible with dual-link DVI input. Most of the rest of the CrossFire hardware is either unchanged or only slightly altered. From a board layout stand point, it would certainly make more sense if ATI were to build GPU to GPU communication into their parts as NVIDIA has done with SLI. Incorporating a silicon version of their compositing engine onto their GPUs would save board space and could improve performance even more.
From a high level, the X1800 CrossFire edition can be paired with a regular X1800 XT or an X1800 XL. There isn't a cheaper CrossFire card for the cheaper X1800 XL, and in order to get CrossFire setup and running with the X1800 XL, half of the RAM on the card needs to be disabled. In order to disable the RAM, the system needs to be rebooted, but in other cases CrossFire can be enabled and disabled without rebooting. While adding a CrossFire card to one's existing X1800 XL setup will definitely increase performance, it is ends up delivering even less for your money than when pairing it with an X1800 XT. The price tag is already a bit hefty, and we expect that most people who want this card will be those who need the absolute maximum performance possible. The value of CrossFire as an upgrade won't really be worth it unless the price of the X1800 CrossFire card comes down quite a bit.
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Vol2005 - Tuesday, December 20, 2005 - link
Dunno what about 512gtx-Sli, but single one is http://www.pcpop.com/doc/0/121/121711_5.shtml">no more "the best of the best" since "eax 1800xt top" beat it in most d3d benchies. ( not to mention it's price some $20-50 more than standard xt)Fenixgoon - Tuesday, December 20, 2005 - link
D3D benches are different than real world performance - and for just about everything (if not everything, correct me if i'm wrong), the GTX 512 blows away the GTX 256 and x1800XT. The x1800 XTPE, or whatever's next in line, is *supposed* to compete with the GTX512. Almost seems like nvidia caught ati flat footed on this one.Vol2005 - Wednesday, December 21, 2005 - link
sorry, maybe i was a bit unclearbut the thing is that asus x1800xt-top IS x1800xtpe, indeed. And as you've just said the real competitor to gtx512 according to article that i refered.
As to real world perfomance, it's still uclear to me what do you mean.
Maybe i'm wrong, but aren't the majority of the modern games using d3d? Even if not so, i think these results are fairly enough prove that the gtx is no longer the fastest.
Of course, this has to be proven further by other reviewers
bob661 - Tuesday, December 20, 2005 - link
You should've bought it when it was released. It was available then. Nothing mystical here.Leper Messiah - Tuesday, December 20, 2005 - link
6 frame per second increase in 1920x1440? eh?Tanclearas - Tuesday, December 20, 2005 - link
Come on! There are over 100 people in EVGA's step-up queue waiting for the 7800GTX 512MB, but you have a problem with ATI's availability?!Nvidia got LUCKY with the 256MB 7800GTX that it was ready to launch with no real competition. Nvidia was able to sit on it until sufficient quantity were ready. ATI (sort of) launches the X1800XT and Nvidia falls back to the same old launch tricks. If you're going to hold one company accountable, you have to hold them all accountable!
bob661 - Tuesday, December 20, 2005 - link
LOL! That's some retarded logic you got there pal.Tanclearas - Tuesday, December 20, 2005 - link
So you're saying Nvidia's should not be held accountable for supply issues, but ATI should be held accountable? Please tell me you were being sarcastic.bob661 - Tuesday, December 20, 2005 - link
I'm saying it's retarded because when Nvidia released their cards, you could buy them that day. Unlike ATI that even SAYS it will be different this time around and STILL fails to deliver. If neither companies produce enough to meet demand then they underestimated demand and that's something different entirely.Tanclearas - Tuesday, December 20, 2005 - link
So ATI could have shipped about five cards to the top 10 retailers, and ATI would have completely fulfilled your expectations. They just would have "underestimated demand".That's a huge load of crap you're shovelling there. Both companies are still more interested in appearing to be in a leadership position than they are actually ensuring they are making deliverable products. I just can't understand why so many "journalists" have their heads shoved so far up Nvidia's ass they can count their fillings.