Crossfire Info

[Charmaka]

Driverheaven:

You arent gaming right now with two 6800s in SLi are you? How important do you personally feel dual card is going to be this or next year?

Jimmy:

I am not a big fan of SLI, since the upgrade investment doesn't give way to many benefits, i.e. only about 2.5% of games get a performance increase, you have to buy both cards from the same manufacturer, many games actually experience a performance decrease, some 6800 and 6600s don’t have SLi connectors, etc. With CrossFire, you get a performance gain on any 3D game you play, it works with any X800 or X850 card, and you can take advantage of Super AA mode, which provides up to 14X AA.

I think "works with any card" is a bit disingenuous at this point. Once you have the master card, they you are indeed free to buy any card. However, right now no one has master cards. For millions of people, the starting point of X-fire setup will be an X800 or X850 card they already own. And in their cases, they can't just by "any card" - they need the appropriate master card. With SLI, you are free to choose you starting card, which will lock you in into your second card. With Xfire, you are free to chose your slave card, but get no choice of master card. Maybe I am looking at it from a wrong perspective, but it seems that with either setup you can chose one card and the other will be chosen for you by the system restriction.

BTW, I was not aware of 6800/6600 PCI-E cards shipping without SLI connectors. What OEMs sell such cards?

If it was guaranteed that all SLI-ready cards on the market today would be available in quantity a year or two down the line, then the "needs an identical card" issue would be for practical purposes irrelevant - you'd buy the best card on the market today, and you'd pick up a pair in a year's time.
The reason why it is a big issue is that it's very possible that you'll buy a card today and then, a year later, find a pair isn't available. Then you're screwed.

By contrast, the ATI solution only has two possible cards you could want, and these cards will probably be in circulation for a good long time as they're "Made by ATI" cards and thus will keep coming until ATI decides to stop, which one would imagine will be at least a year and a half, probably two or more, and by that point there'll be enough in circulation that finding one shouldn't be a huge deal. That's why it's relevant.

 

[ANova]

given only AFR is usable, you'd have : (let's call A the x850xt and B the X300SE)

t=0
A starts to renders a frame
B starts another frame
t=10ms
A output its frame
A is waiting and getting extremely bored.
t=120ms
B outputs its frame.

The only sensible thing to do in this case would be to tell A it can keep rendering however many frames it can in the same amount of time as card B can render one frame. That way there would be no loss, only gain. Albeit a small gain with this particular setup. Of course this would only work with some modes like AFR, but not supertiling.

 

[Charmaka]

given only AFR is usable, you'd have : (let's call A the x850xt and B the X300SE)

t=0
A starts to renders a frame
B starts another frame
t=10ms
A output its frame
A is waiting and getting extremely bored.
t=120ms
B outputs its frame.

The only sensible thing to do in this case would be to tell A it can keep rendering however many frames it can in the same amount of time as card B can render one frame. That way there would be no loss, only gain. Albeit a small gain with this particular setup. Of course this would only work with some modes like AFR, but not supertiling.

That's either going to result in out-of-order frames or bursts of frames every few milliseconds.

 

[trinibwoy]

The only sensible thing to do in this case would be to tell A it can keep rendering however many frames it can in the same amount of time as card B can render one frame. That way there would be no loss, only gain. Albeit a small gain with this particular setup. Of course this would only work with some modes like AFR, but not supertiling.

Not going to work. The slower cards frame is going to come way out of sync. Unless you expect the cpu to guess what the input 10 frames from now will be and send that to the slow card

 

[DemoCoder]

It's a great way for offline single player games to experience "jump back" lag effects tho!

 

[trinibwoy]

It's a great way for offline single player games to experience "jump back" lag effects tho!

It'll be more like a flashback since the next frame will be in the "future"

 

[Geo]

We easily could have put 512MB on the X850 products, but with our next generation architecture on the horizon, we thought it would be best to wait.

Gee, I wonder what else such logic could apply to.

 

[Mark]

I was, of course, not serious when I said X850+X300. A much more practical combination would be X850XT+X800XTPE or some such thing that is currently "not allowed" for some reason or another.

 

[ANova]

The only sensible thing to do in this case would be to tell A it can keep rendering however many frames it can in the same amount of time as card B can render one frame. That way there would be no loss, only gain. Albeit a small gain with this particular setup. Of course this would only work with some modes like AFR, but not supertiling.

Not going to work. The slower cards frame is going to come way out of sync. Unless you expect the cpu to guess what the input 10 frames from now will be and send that to the slow card

That's theoretical of course. I never claimed it to be easy, or even possible.

 

[Dave Baumann]

Discussions about PDF's and their creation move here.

 

[Dave Baumann]

Theoretical you can do 4xMSAA and 4xSSAA to get 16xAA on gf6(20x in ati terms)

This mode is neing enabled for SLI systems in some upcoming drivers.

 

[Geo]

Theoretical you can do 4xMSAA and 4xSSAA to get 16xAA on gf6(20x in ati terms)

This mode is neing enabled for SLI systems in some upcoming drivers.

Now this is the kind of "King of the Hill" competition that I can support. . .

 

[trinibwoy]

Theoretical you can do 4xMSAA and 4xSSAA to get 16xAA on gf6(20x in ati terms)

This mode is neing enabled for SLI systems in some upcoming drivers.

Now this is the kind of "King of the Hill" competition that I can support. . .

That's not really a big deal since most people with SLI would have accessed this mode already. Hopefully the "official" support comes with some performance improvements.

 

[no-X]

http://www.hkepc.com/hwdb/ati-crossfire-5.htm

 

[Geo]

http://www.hkepc.com/hwdb/ati-crossfire-5.htm

I sense a "we scale better!" chest-beating coming on from the NV camp. . .

 

[CJ]

And ATi has the excuse of CrossFire beta-drivers.

 

[Geo]

And ATi has the excuse of CrossFire beta-drivers.

You mean for those who prefer the unproven possibility of future improvements from buggy, immature technology rather than enjoying proven, mature solutions powering thousands of happy gamers systems?

 

[Rys]

You mean for those who prefer the unproven possibility of future improvements from buggy, immature technology rather than enjoying proven, mature solutions powering thousands of happy gamers systems?

Expect a call from DP offering you a job

 

[Geo]

You mean for those who prefer the unproven possibility of future improvements from buggy, immature technology rather than enjoying proven, mature solutions powering thousands of happy gamers systems?

Expect a call from DP offering you a job

Oh, I doubt it --my ability to spin is limited by the truth.

 

[no-X]

Almost whole year of driver-tuning, bug-fixing, cheating and SLI systems still provide only 6% better scalability, than ATi's new, buggy and immature technology?