HardOCP Crossfire review up

[nts]

Originally posted by: Rollo
Sorry I have no link, if you look around at reviews though you'll see the general consensus that tiling is not as desirable

Haven't seen the reviews mention tiling...

as it offers no increase in geometry processing power like AFR does. (duplicatrion of geometry processing )

geometry is duplicated in both cases, AFR duplicates it and Tiling duplicates it...

 

[nRollo]

Originally posted by: nts

Originally posted by: Rollo
Sorry I have no link, if you look around at reviews though you'll see the general consensus that tiling is not as desirable

Haven't seen the reviews mention tiling...

as it offers no increase in geometry processing power like AFR does. (duplicatrion of geometry processing )

geometry is duplicated in both cases, AFR duplicates it and Tiling duplicates it...

Hmmm. That's not what I thought. (but info is harder to find on this than I thought)

http://www.behardware.com/articles/590-2/ati-crossfire-the-test.html

SuperTiling consists of dividing the picture into a ?drafting board?. Half of the squares are calculated by one GPU and the other half by the other. It suffers from the same limitations as SFR, meaning that it doesn?t increase the geometric calculation power (unlike AFR). As ATI doesn?t have a SFR dynamic mode, SuperTiling helps to increase efficiency in that statistically, the load is automatically shared equally between the two graphic cards.

So with Crossfire, two of the three methods are worse than nVidias dominant AFR methods. (not to mention you can force AFR on any app with SLI)

ATI Tiling - Duplicates geometry processing, less gain than AFR
ATI SFR- not dynamic, low compatibility, only available in predefined ratios on profiled games
ATI AFR- no problem

 

[RobertR1]

If the performance is there and IQ is not sacrificed, what's the big deal???

 

[nRollo]

Originally posted by: RobertR1
If the performance is there and IQ is not sacrificed, what's the big deal???

I guess that is something you would have to ask nearly every person who has said they don't like SLI because it doesn't offer 100% improvement over single card RobertR1.

AFR comes the closest to offering that, it's often 50-90% improvement, depending on the game.

Tiling you'll be lucky to get 50%. (each card is rendering half the frame, but all the geometry)

ATI defaults to Tiling on every non profiled D3d game, most of them, and you can't change it with Crossfire. (in SLI you can)

So the argument we see most often against SLI (not offering double framerates) is especially true for Crossfire. I don't think even ATI staff would disagree with me on this one.

The games you see reviewed are new, often benched ones that largely have AFR profiles and show Crossfire at it's BEST. We don't know yet how many profiles there are in Catalyst AFAIK, but you can't create new ones or force a mode AFAIK.

 

[nts]

Originally posted by: Rollo
Tiling you'll be lucky to get 50%. (each card is rendering half the frame, but all the geometry)

Still looking to see benchmarks for it, looks like an interesting solution (far better than SFR).

btw with AFR the same geometry is sent to both cards, one just doesn't use it on the current frame (or uses it but dumps the final output). Imagine what would happen if you had different versions of the same geometry on each card.

ATI defaults to Tiling on every non profiled D3d game, most of them, and you can't change it with Crossfire. (in SLI you can)

And NVIDIA defaults to nothing?

Tiling works in all cases so why not use it when you don't have a profile available? Forcing modes is not going to work all the time and is highly dependant on the game.

btw which D3D games use tiling because I haven't seen them benched?

The games you see reviewed are new, often benched ones that largely have AFR profiles and show Crossfire at it's BEST. We don't know yet how many profiles there are in Catalyst AFAIK, but you can't create new ones or force a mode AFAIK.

On early SLI you couldn't either, so give it time.

 

[nRollo]

I've looked into it more and we're both partially right nts.

Like I said:

http://www.digit-life.com/articles2/video/crossfire.html
Re: Tiling

Does not distribute geometrical load and thus requires significant reserve of geometric efficiency.

But the geometric load has to be replicated by VPUs ? both accelerators calculate the same geometry

Re:AFR

Distributes both pixel and geometric load; geometry data transferred along the bus is not duplicated ? different accelerators get different data sets

The article does say that Tiling is good for fill rate limited games, bad for geometry/vertex limited games.

My main problem, as noted, is not having the ability to decide. If ATIs default doesn't work with a non profiled game, you're done using Xfire with that game.

With Coolbits enabled, you can set a default mode for non profiled with SLI.

It should also be noted that if ATI's SFR is not dynamic, only preset by profile which limits it's benefit.

As for Crossfire not having profiles yet, do you think what it offers today adequately offsets the wait for profiles, stability, AA+HDR patches, maybe default flexibility?

Not me, that's why I created this thread.

 

[RobertR1]

Just as the R520 improved considerably with driver over a few months, I expect the same from Crossfire. Unfortunately, I don't think crossfire will get the same coverage when it does start to perform better since it's obviously more fun to slander a product and lable it incompetant right at launch. Certainly was the case with the R520 when it was first released.....esp. on these forums.

Sli had plenty features and wish list items that came with drivers laters but people seem to forget that. If I recall, it was only recently they added the vsync suport and different vendor support for Sli. It's ok for nvidia to take upto a year to mature it's drivers but Ati must be not less than perfect on it's first shot or get slammed??? which is really what's happening here.

 

[Wreckage]

Originally posted by: nts
And NVIDIA defaults to nothing?

Tiling works in all cases so why not use it when you don't have a profile available? Forcing modes is not going to work all the time and is highly dependant on the game.

http://www.techreport.com/reviews/2005q3/ati-crossfire/index.x?pg=20

Unfortunately, the default SuperTiling mode doesn't scale well at all, in our experience, so the prospect of CrossFire "just working" with any application whatsoever seems a little bit far-fetched.

BAM!@

 

[nRollo]

That digit life article had some inaccurate info in it ["SLI only works on a few games", etc]
so I found another to back up the geometry claim:
http://techreport.com/etc/2005q2/ati-crossfire/index.x?pg=1

Supertiling ? This is the tiling mode built into the original R300 VPU and used by ATI partner Evans & Sutherland in its high-end visualization systems. The screen is split up into 32x32 tiles and the workload is distributed according to a checkerboard-style pattern, with one card taking what would be the black squares and the other the squares that would be red. Splitting up the workload in such relatively small tiles should result in a distribution of the load that's very close to an even split, and it should allow two cards to produce markedly higher fill rates and pixel shader throughputs than a single card. The vertex processing load will be duplicated on each card, however, so that a CrossFire system with supertiling won't likely achieve any higher geometry throughput than a single card.

 

[nRollo]

Originally posted by: RobertR1
Just as the R520 improved considerably with driver over a few months, I expect the same from Crossfire. Unfortunately, I don't think crossfire will get the same coverage when it does start to perform better since it's obviously more fun to slander a product and lable it incompetant right at launch. Certainly was the case with the R520 when it was first released.....esp. on these forums.

Sli had plenty features and wish list items that came with drivers laters but people seem to forget that. If I recall, it was only recently they added the vsync suport and different vendor support for Sli. It's ok for nvidia to take upto a year to mature it's drivers but Ati must be not less than perfect on it's first shot or get slammed??? which is really what's happening here.

Not from me.

I think X1800XTs are very nice cards, and realize Crossfire may get better in time. (and I hope it does)

This thread is about warning people considering a GTX vs Crossfire rig right now that there are a lot of problems with Crossfire currently, that may or may not be fixed soon. (i.e. Crossfire is currently a gameble)

Got $500 you want to spend on a single graphics card? X1800XT is a fine choice, unless you're a noise-phobe.

Got $1000 to spend on multi GPU? I can't recommend Crossfire today. Maybe I can in 6 months, maybe not. Time will tell and this is the only message I'm trying to convey with this thread.

To call that "biased" or "fanboy" would seem to me connotative of the accusers agenda. It's the truth, it gives ATI credit where it's due.

 

[Keysplayr]

Originally posted by: RobertR1
Just as the R520 improved considerably with driver over a few months, I expect the same from Crossfire. Unfortunately, I don't think crossfire will get the same coverage when it does start to perform better since it's obviously more fun to slander a product and lable it incompetant right at launch. Certainly was the case with the R520 when it was first released.....esp. on these forums.

Sli had plenty features and wish list items that came with drivers laters but people seem to forget that. If I recall, it was only recently they added the vsync suport and different vendor support for Sli. It's ok for nvidia to take upto a year to mature it's drivers but Ati must be not less than perfect on it's first shot or get slammed??? which is really what's happening here.

So, a year you say. So why not wait til next year to even consider Xfire then? By your logic that is. Why complain when people are complaining about xfire now?

 

[RobertR1]

Originally posted by: keysplayr2003

Originally posted by: RobertR1
Just as the R520 improved considerably with driver over a few months, I expect the same from Crossfire. Unfortunately, I don't think crossfire will get the same coverage when it does start to perform better since it's obviously more fun to slander a product and lable it incompetant right at launch. Certainly was the case with the R520 when it was first released.....esp. on these forums.

Sli had plenty features and wish list items that came with drivers laters but people seem to forget that. If I recall, it was only recently they added the vsync suport and different vendor support for Sli. It's ok for nvidia to take upto a year to mature it's drivers but Ati must be not less than perfect on it's first shot or get slammed??? which is really what's happening here.

So, a year you say. So why not wait til next year to even consider Xfire then? By your logic that is. Why complain when people are complaining about xfire now?

When did I say a year for crossfire? The nvidia example was just to demonstrate the importance of driver maturity. Without competition, nvidia had the luxury to take upto a year to introduce new features to Sli. Obviously, Ati cannot wait a whole year to improve crossfire. They need accomplish in 2-3months, what nvidia had a whole years head start with, in order to compete.

If anyone expected Crossfire to be on par with Sli upon first release (I really don't count the x850 xfire solution anything but PR garbage) they are quite dense.

 

[Keysplayr]

Originally posted by: RobertR1

Originally posted by: keysplayr2003

Originally posted by: RobertR1
Just as the R520 improved considerably with driver over a few months, I expect the same from Crossfire. Unfortunately, I don't think crossfire will get the same coverage when it does start to perform better since it's obviously more fun to slander a product and lable it incompetant right at launch. Certainly was the case with the R520 when it was first released.....esp. on these forums.

Sli had plenty features and wish list items that came with drivers laters but people seem to forget that. If I recall, it was only recently they added the vsync suport and different vendor support for Sli. It's ok for nvidia to take upto a year to mature it's drivers but Ati must be not less than perfect on it's first shot or get slammed??? which is really what's happening here.

So, a year you say. So why not wait til next year to even consider Xfire then? By your logic that is. Why complain when people are complaining about xfire now?

When did I say a year for crossfire? The nvidia example was just to demonstrate the importance of driver maturity. Without competition, nvidia had the luxury to take upto a year to introduce new features to Sli. Obviously, Ati cannot wait a whole year to improve crossfire. They need accomplish in 2-3months, what nvidia had a whole years head start with, in order to compete.

If anyone expected Crossfire to be on par with Sli upon first release (I really don't count the x850 xfire solution anything but PR garbage) they are quite dense.

All the more reason to wait at least two to three months to even consider Xfire as a purchase option. Let's see if ATI can do in 3 months what it took Nvidia's team a year. You and I both know what happens when you rush things right? Dongle?

 

[RobertR1]

Originally posted by: keysplayr2003

Originally posted by: RobertR1

Originally posted by: keysplayr2003

Originally posted by: RobertR1
Just as the R520 improved considerably with driver over a few months, I expect the same from Crossfire. Unfortunately, I don't think crossfire will get the same coverage when it does start to perform better since it's obviously more fun to slander a product and lable it incompetant right at launch. Certainly was the case with the R520 when it was first released.....esp. on these forums.

Sli had plenty features and wish list items that came with drivers laters but people seem to forget that. If I recall, it was only recently they added the vsync suport and different vendor support for Sli. It's ok for nvidia to take upto a year to mature it's drivers but Ati must be not less than perfect on it's first shot or get slammed??? which is really what's happening here.

So, a year you say. So why not wait til next year to even consider Xfire then? By your logic that is. Why complain when people are complaining about xfire now?

When did I say a year for crossfire? The nvidia example was just to demonstrate the importance of driver maturity. Without competition, nvidia had the luxury to take upto a year to introduce new features to Sli. Obviously, Ati cannot wait a whole year to improve crossfire. They need accomplish in 2-3months, what nvidia had a whole years head start with, in order to compete.

If anyone expected Crossfire to be on par with Sli upon first release (I really don't count the x850 xfire solution anything but PR garbage) they are quite dense.

All the more reason to wait at least two to three months to even consider Xfire as a purchase option. Let's see if ATI can do in 3 months what it took Nvidia's team a year. You and I both know what happens when you rush things right? Dongle?

Yeah, the dongle idea is a bit silly but if the performance is there, it won't be a big issue for most buyers. I'll be really curious to see how and if crossfire matures in a few months. I personally am not in the market for either dual gpu solution but it's fun to watch the competition. Would be real interesting if some of partners started offering discounts for Sli/crossfire bundles.......

 

[Matthias99]

Originally posted by: keysplayr2003
You and I both know what happens when you rush things right? Dongle?

:disgust:

ATI uses a different multi-card setup than NVIDIA, which has pluses and minuses. In particular, Crossfire should take significantly less of a performance hit from their SuperAA modes (and may have lower CPU overhead) due to the standalone compositing engine, and the FPGA chip they use can be reprogrammed in the field. The downside is that because of the extra cost, they went with separate 'master' cards, and because they need a full DVI link between the cards, ATI decided to make the inter-card connection cable external to the case.

"OMG crossfire has dongles and master cards so its teh suck" is not useful in terms of technical discussion on this topic. It was a conscious choice on their part, not some hack they put in because they couldn't do it "correctly".

 

[schtuga]

I agree with you matthias,the end result is what counts.

What I find funny was how when sli first came out it was

"too expensive""will never work" and my fave "it's just a fad that will die faster than 3dfx"

Of course that has all changed now that ATI has something comparable.

 

[Munky]

Both Crossfire and SLI are primitive first attempts at a dual gpu solution, mainly limited by current process methods and cost, IMO of course. I'd be much more inclined to buy a dual gpu solution if it was designed as 2 gpu's on one card (like the asus dual gt), with mature drivers that make it work right out of the box, and no need to deal with the hassle of dongles, bridges, extra cost motherboards, and enablind/disabling SLI on the mobo. Obviously, there are economic issues involved as it's a lot easier to sell one 7800gt and possibly 2, than it is to sell 1 super-gt to the small minority of enthusiasts. But in the next few years I would not be surprised if the vendors adopted multiple gpu's on one card instead of developing increasingly complex single gpu's.

 

[Matthias99]

Originally posted by: schtuga
What I find funny was how when sli first came out it was

"too expensive""will never work" and my fave "it's just a fad that will die faster than 3dfx"

Well, given the bugs around it (and the extra expense of SLI motherboards when they first came out), much of the early criticism was valid. However, if you could deal with the various bugs and quirks, it was clearly the best choice in terms of performance if money was no object.

IMO, the only place multi-card solutions (or the 'SLI-on-a-card' hackjobs) make sense is in the super-high-performance area (where you are trying to get more performance than is possible on a single card). So far, it has never turned out to be a particularly attractive upgrade path by the time the next generation of cards has rolled around.

Of course that has all changed now that ATI has something comparable.

There's also the fact that SLI seems to work reasonably well at this point.

 

[Keysplayr]

Originally posted by: Matthias99

Originally posted by: keysplayr2003
You and I both know what happens when you rush things right? Dongle?

:disgust:

ATI uses a different multi-card setup than NVIDIA, which has pluses and minuses. In particular, Crossfire should take significantly less of a performance hit from their SuperAA modes (and may have lower CPU overhead) due to the standalone compositing engine, and the FPGA chip they use can be reprogrammed in the field. The downside is that because of the extra cost, they went with separate 'master' cards, and because they need a full DVI link between the cards, ATI decided to make the inter-card connection cable external to the case.

"OMG crossfire has dongles and master cards so its teh suck" is not useful in terms of technical discussion on this topic. It was a conscious choice on their part, not some hack they put in because they couldn't do it "correctly".

Matthias, don't roll your eyes at me. I am not questioning the performance (current/potential) of crossfire. I'm saying that compared to the way SLI "looks", Xfire looks like an "afterthought" and a "we'll just stick this here and put this there" type of solution. MY OPINION.

 

[Ackmed]

Except that 3DFX's SLI used an external type of cable, and even a cable that connected the cards inside the PC. It had no competition, so I doubt it was "rushed". I understand that its your opinion it has the dongle because it was rushed, but past evidence shows that the only other previous time, it doesnt look like that was the case.

Personally its my opinion that people are making a big issue out of a little one. Ive seen some of the PC's from people who complain about the dongle, and wire management isnt their top priority. In fact, Id go as far as saying the inside of their PC's look like rats nests. So a wire on the backside of the PC shouldnt be an issue...

 

[John Reynolds]

I don't understand the fixation on the dongle either. My first concern would be the noise level coming off of two X1800 XTs under load if I were considering a high-end X-fire setup.

 

[Matthias99]

Originally posted by: keysplayr2003
Matthias, don't roll your eyes at me. I am not questioning the performance (current/potential) of crossfire. I'm saying that compared to the way SLI "looks", Xfire looks like an "afterthought" and a "we'll just stick this here and put this there" type of solution. MY OPINION.

Well, then you should have no problem with my opinion being that your opinion is full of it. IMO, of course.

From a technology standpoint, the way ATI is doing things may actually end up giving better performance, especially with SuperAA. Calling it a 'rush job' or 'afterthought' because it has an external connection (as opposed to internal) between the cards is a little silly.

 

[Keysplayr]

Originally posted by: Matthias99

Originally posted by: keysplayr2003
Matthias, don't roll your eyes at me. I am not questioning the performance (current/potential) of crossfire. I'm saying that compared to the way SLI "looks", Xfire looks like an "afterthought" and a "we'll just stick this here and put this there" type of solution. MY OPINION.

Well, then you should have no problem with my opinion being that your opinion is full of it. IMO, of course.

From a technology standpoint, the way ATI is doing things may actually end up giving better performance, especially with SuperAA. Calling it a 'rush job' or 'afterthought' because it has an external connection (as opposed to internal) between the cards is a little silly.

What I think is a little silly, is you questioning my opinion. You have gained no ground in changing it with your 'tude. So don't waste your time.

 

[nRollo]

Originally posted by: Matthias99

Originally posted by: keysplayr2003
Matthias, don't roll your eyes at me. I am not questioning the performance (current/potential) of crossfire. I'm saying that compared to the way SLI "looks", Xfire looks like an "afterthought" and a "we'll just stick this here and put this there" type of solution. MY OPINION.

Well, then you should have no problem with my opinion being that your opinion is full of it. IMO, of course.

From a technology standpoint, the way ATI is doing things may actually end up giving better performance, especially with SuperAA. Calling it a 'rush job' or 'afterthought' because it has an external connection (as opposed to internal) between the cards is a little silly.

I think 90%+ of the reviews I see don't like the whole dongle Master compositer mess, so he's in good company.

I don't care much about the bolt on nature of Crossfire, or the heat and noise.

What bothers me about Crossfire is the way it works besides the SuperAA, which works great.

 

[Keysplayr]

Do you have any idea how much better xfire would appeal to consumers and reviewers alike if ATI substituted the external dongle with an internal interconnect solution? It is FAR more elegant to do so. Sure, people say "It doesn't bother them to have a dongle, who looks in the back of their computer anyway?" But then ask them, given a choice, would they prefer an internal connector or the dongle? If anyone says they prefer the dongle, then that person is absolutely full of it. But because they have NO choice currently with Xfire, and HAVE to have an external cable to connect them, then of course their response will be, "It really doesn't bother me.". I am speaking of ATI fans who want to see ATI do better than Nvidia. Xfire is sloppy in comparison in it's current incarnation. Performance seems to be there, but it's just sloppy IMHO. Maybe 1 or 2 gens of xfire down the road, and some ATI engineer will see the light.