Final Words

SLI was not without its hiccups at the outset. Since NVIDIA launched its dual GPU solution a year ago, things have only gotten better. The first few months of CrossFire have shown us that ATI is struggling down the same road that NVIDIA set out on with SLI. The first version of CrossFire wasn't as refined as we had hoped it would be, but everyone has to start somewhere. The X1800 CrossFire Edition card shows that ATI is making significant progress in the multi GPU arena.

The system level problems and difficulty we had with the initial version of CrossFire were largely solved this time around, as (after a proper BIOS update) we had no trouble enabling CrossFire or getting it running. The reboot required for getting the card to work with the 256MB X1800 XL is a bit of a step backward, but it's nothing major. Super AA modes work, but aren't worth it in games that see a performance benefit from more than one GPU. These modes haven't changed from the original X800 CrossFire release, but now AA mode blending is done in hardware as well.

Unfortunately, there are still some real down sides. Aside from not hurting performance, there should be absolutely no game that suffers a performance hit from enabling CrossFire. This kind of problem was one of the issues we saw with NVIDIA's SLI when it first came out and selecting the wrong mode could cause performance issues (though we never saw anything as dramatically catastrophic as CrossFire's performance under Black and White 2). Hopefully ATI can fix all of this with some additions or changes to the application detection in Catalyst A.I.

There isn't as much capacity for customization of how CrossFire affects a particular game. Sure, we could probably figure out how to perform some sort of registry hack to force CrossFire to enable a specific mode, but NVIDIA's drop down menu is so much more efficient. I do agree that it is usually best to let the driver and application figure out what to do, but clearly there are some cases where things can go wrong. More finely grained customization is something we have been looking for from ATI in general, but as systems get more complex (such as in the case of multi GPU solutions), it is even more important to give the end user more control with solid default functionality.

We still don't like the external dongle as much as NVIDIA's internal bridge (especially the flexible kind). While our lab sports an excessive number of cables running everywhere, we are sure that less clutter behind the machine is better for everyone. And GPU to GPU communication does have board space and other advantages as well. Thankfully, this time around we are able to squeeze dual-link DVI bandwidth in to and out of the cable. While mastercardless CrossFire is in ATI's future, it is unclear yet what kind of performance or quality impact this will have on the overall solution.

Performance is one of the high points of CrossFire in general. In many cases, the X1800 XT in CrossFire performs between the 7800 GTX SLI and 7800 GTX 512 SLI setups. Things may heat up even more when ATI brings out its R500 series refresh part to compete more directly with NVIDIA's top of the line king of the hill GeForce 7800 GTX 512.

But price is still an issue for ATI at the high end. With the 7800 GTX selling for between $450 and $500, finding two that fall somewhere between $900 and $1000 isn't a difficult task. With the X1800 CrossFire Edition at about $600 and the price of standard X1800 XT running between $500 and $550, shelling out $1100 or more dollars for CrossFire isn't a stretch. Unless the system is just made to eat money, one or two hundred dollars is a good savings for a comparable solution that is much more mature. And for those who want the best of the best (and really can afford to burn money), that's still going to be the $1400 dual 7800 GTX 512 setup.

And above all of this looms the shadow of availability. After an early morning look around, it doesn't look good. Some vendors have X1800 CrossFire Edition cards listed on their site, but they are all showing out of stock, back ordered, or early January ETAs on parts. With previous NVIDIA launches, we have seen product available for purchase before we published. With the 7800 GT launch, we even had parts listed for sale in our RTPE the weekend before we could talk about it. Without seeing anywhere to physically buy the hardware just hours before it is supposed to be publicly available does not give us a warm and fuzzy feeling about ATI's promises. But we are good sports, so we will keep checking throughout the day for any sign of an online vendor actually selling parts. ATI knows how important this launch is in earning some level of trust back from the press and their customers. All we can do at this point is hope that translates into results.

UPDATE: To put things bluntly, we aren't exactly certain how to react to this luanch. On Tuesday, there was very limited availability at one or two online retailers. Most major sites listed availability as "out of stock" or "backorder", but if you looked hard enough you could find a card for sale. We have to give ATI credit for this, as its much more than we've seen in the past. The day after launch more sites have the X1800 CrossFire edition available for immediate purchase. The situation is a little better, but not quite on par with the 7800 GT or 6800 GS launches. We all know the 7800 GTX 512 is all but impossible to find right now, but people who got in there quickly were able to get product at launch. Neither the 7800 GTX 512 situation nor this X1800 CrossFire launch are what we really want: immediate availability of parts in high enough quantities to at least to meet demand. Yes, it is quite a bit to ask, but NVIDIA has shown us it can be done with 7800 GTX, GT, and 6800 GS launches. Yes, it is the holiday season, so we understand that the pressure and difficulty of delievering what we want is increased orders of magnitude over the already difficult process of hard launching a part. So what's our final assesment?

For now, this is enough. We commend ATI for coming through and getting some cards out there at launch. But we still want to see more improvement in the future.


Quake 4 Performance
Comments Locked

40 Comments

View All Comments

  • almvtb - Tuesday, December 20, 2005 - link

    Has anyone ever compared SLI and crossfire performance using a dual core compared to just a single core cpu? I mean if there is enough overhead for sli or crossfire a dual core chip could improve performance.
  • kristof007 - Tuesday, December 20, 2005 - link

    I don't know if that dual core thing would work. I mean it might but the two slower CPUs would not help in my opinion. Games are single threaded so the multi CPU wouldn't take off the overhead .. at least that's my knowledge of it.
  • almvtb - Tuesday, December 20, 2005 - link

    See I thought that was a big deal with one of the latest Nvidia driver releases. That it was made multithreaded so that in a situation such as when you have sli or any other kind of driver overhead it would be taken care of by the a second core if one existed. I do not know it was just a thought that i had never seen discussed, so I thought I would ask.
  • bob661 - Tuesday, December 20, 2005 - link

    That was an ATI driver release that had the multithreading stuff, I think.
  • kilkennycat - Tuesday, December 20, 2005 - link

    We shall shortly soon find out whether Crossfire is serious or just a ATi marketing straw-grabbing ploy to get some suckers (er, "enthusiasts") not to buy SLI. If the compositor is fully integrated into EVERY R580 GPU, (thus never requiring a masterboard and implementing the board communications via a passive bridge a la nVidia) then we shall finally know that ATI is serious with Crossfire. It was probably a stupid cheese-pairing management decision not to integrate the Crossfire functionality fully into the R520 GPU, or else Crossfire does not have enthusiastic support from ATI engineering and is purely a ATi marketing ploy anyway. The R580 details will reveal the truth.
  • Spacecomber - Tuesday, December 20, 2005 - link

    What changed since the http://www.anandtech.com/video/showdoc.aspx?i=2466...">Battlefield 2 GPU Performance Analysis article? It seemed like you were able to demonstrate the advantages of SLI in those benchmarks.

    Space
  • bob661 - Tuesday, December 20, 2005 - link

    I think AT has a different benchmark now for BF2.
  • Spacecomber - Thursday, December 22, 2005 - link

    As far as I know the only thing that has changed along the way are the addition of BF2 patches (according to the overclocking the Athlon X2 article, they are up to using the 1.03 patch) and newer nvidia drivers. I believe they are still creating a demo and running it with the timedemo option. With this being such a popular game (BF2), it seems like it would be worthwhile to confirm whether SLI/Crossfire does or does not offer significant improvements for BF2.
  • ViRGE - Wednesday, December 21, 2005 - link

    Ya, DICE seems to screw up demos with new BF2 patches.
  • ElFenix - Tuesday, December 20, 2005 - link

    i wonder if you can change b&w2's name to make the score go up as well. maybe there is poor optimization going on in the catalyst AI?

Log in

Don't have an account? Sign up now