Thoughts
Hmmmmmmmmmmmmmm, so what do I, and by extension the mighty HEXUS.core, think about X1800 Crossfire? Let's ponder the good stuff first. SuperAA performance is pretty excellent now, instead of rubbish. Game performance scaling is pretty much mighty, and an easy enough match for high-end SLI in terms of the boost you can get and the overall performance levels at the end of it. Those things are now good, by virtue of new FPGA programming and the general speed of XT-spec R520.However - with that word carrying so much weight here - there's a truckload of niggles to consider. The form factor stuff is fairly obnoxious. Wire density in the connecting cable, since it carries a pair of DVI channels in to one connector, means the bending you need to do to connect two boards right next to each other is fearsome. Actually getting the two boards hooked up together is an exercise in frustration and fiddly screwing with a small-tipped driver. That simply doesn't exist with SLI.
Then there's the noise that two X1800 XTs make when you push them as hard as you can, which is the whole point of the setup in the first place. The conclusions we came to here, on the heat and noise of one board, are pretty much doubled in Crossfire. I wouldn't live with two in the same system, frankly, and anyone with ears would say much the same. Two GTXs or GTX 512s in SLI is comparatively lovely in the noise stakes, even with the boards at full chat.
The driver was also a pain, especially when learning the rules about turning Crossfire on and off the easiest ways. If you always want it on, no worries. Otherwise it's not always tick the box and hit Apply. The reviewer's guide even says (and we paraphrase), "please check benchmark results to be sure it's on". With no indication that it's on other than experienced performance, HEXUS learned early on not to trust the checkbox too much. The ATI driver team will work on that I'm sure, but it frustrated. Comparatively, we've never had any such issues with SLI, although it's had longer to mature.
Price and availability wise, it's around $100 more for the Crossfire Edition X1800 XT just now, with availability from next week or so. So $600 for a board, if you fancy it. There's no real reason to bother pairing it with any 256MiB board, too. Not sure why that's a validated setup. Further, there continues to be no way to demonstrate multisample AA and FP surfaces - one of the very key features of ATI's new GPU hardware - which gives us some cause for concern. See page three for more on that and what we've got planned.
Lastly, the shadow of RD580, and whispers of "proper" Crossfire support from that core logic and the next high-end ATI part, linger. It's almost like this is the warmup act. Crossfire 1.5 if you will, to the 1.0 of the first abortive attempt.
I will say, though, that with resolution limitations all gone and performance looking so great, the time when anyone is likely to look at picking up X1800 XT Crossfire is going to be right now. And for those with the money, it's a fine alternative to SLI if you don't mind the foibles. I'd certainly not choose to run it, even if I had the money to do so, but that won't stop some of you from going right ahead. If you do so, it'll be mostly a good experience running around on the high plains of 3D performance.
The basics are there, but the master/slave relationship and all that brings to the table really needs to disappear before Crossfire becomes a serious recommendation. Luckily that's not the case for X1600 and X1300 Crossfire. We'll look at those pairings in due course.
In summary, an interesting proposition for the ATI fan with a bunch of cash, but SLI sees it off from a practical perspective with ease, with NVIDIA's top-end SLI setups just as quick and forthcoming with better IQ as ATI's are (although not to the same absolute levels).
HEXUS Awards
ATI Radeon X1800 Crossfire
ATI Radeon X1800 Crossfire
