Why is SLI so poor?

[rubberduck]

Hi

From the benchmarks I've seen double/triple/quad SLI always seems to perform relatively poorly in my opinion. Now I realise that there will be a limit to what is achievable with a multi card system as opposed to a single card system but is what we see really as good as it gets?

People mention drivers but surely NVIDIA have been working on SLI since they aquired 3dfx all those years ago... shouldn't it be better by now? In terms of % performance increase is it any better now than it was when people had dual voodoo 2s?

 

[Biohazard]

Voodoo2's were better imo than current day SLI if you could compare!

At least back then most games supported Glide, which did do well with two cards. I saw a massive jump in all my games back then, quake 2 caramageddon etc

 

[Rroff]

SLI with 2 cards isn't poor... its a complicated story tho...

Tri SLI is fairly new - whether that will see any real performance gains or not I don't know but nVidia have started to use a new SLI rendering method with the rollout of tri SLI so something might come of it...

The problem with QUAD SLI is the methods used don't work too well with gaming - in a production/workstation rendering environment they would give close to 4x the performance but in gaming you just can't deal with the game data in a way that lends itself to rendering on 4 seperate cards...



OK its only 8500GTs but heres an example that SLI actually does work in the right hands...

The single card scores are from a slightly higher clocked 8500GT than the pair in SLI but even so they still give almost double the performance of the single card...

http://service.futuremark.com/orb/m...=8500GT+Single/SLI&k=14&s=1&l=1&c=-1320537764

Reasons for SLI not giving good gains come down to (in this order):

(A) User error
(B) Bottleneck by other parts of the system i.e. slow CPU
(C) Application written in such a way that normal SLI routines don't work with it (properly or at all)
(D) Lack of support in the drivers for specific applications that fail point C

 

[Biohazard]

I am waiting for drivers that make the best of todays single card, let alone two or three. They need to pause a second, and mature the drivers a bit imo

 

[stevenazari1]

I am waiting for drivers that make the best of todays single card, let alone two or three. They need to pause a second, and mature the drivers a bit imo

thats why I dont think sli/crossfire is a good approach to making more money for gpu companies. by the time a driver has matured to make the card worth while, a new gpu is out, and am I wrong or right in saying the card will only perform as well as the worst card? Im not sure but I thought I read it somewhere

 

[Gerard]

Anandtech were unimpressed with tri sli, gives decent gains in some games but some it gives marginal to no gains, 2560x1600 crysis gained a massive...7% over sli, world in conflict was about 3%. For the extra cash outlay of a card and more than likely a new psu the gains dont seem to justify the cost involved.

http://www.anandtech.com/video/showdoc.aspx?i=3183&p=3

 

[Rroff]

What you fail to mention is the overall gain from all those games is 23.5% and theres going to be plenty more games that show a 20-25% performance gain from tri-sli over sli... not earth shattering but its early days and even the CPU still plays quite a part...

 

[Gerard]

What you fail to mention is the overall gain from all those games is 23.5% and theres going to be plenty more games that show a 20-25% performance gain from tri-sli over sli... not earth shattering but its early days and even the CPU still plays quite a part...

Even with the cpu clocked up i doubt it would make that much of a difference. We're talking 3 £375+ cards here for graphics alone plus a psu costing £130+. People also said it was early days with quad sli and the only thing that gimmick did was dig itself a hole, crawl into it and die.

 

[J.D]

Even with the cpu clocked up i doubt it would make that much of a difference. We're talking 3 £375+ cards here for graphics alone plus a psu costing £130+. People also said it was early days with quad sli and the only thing that gimmick did was dig itself a hole, crawl into it and die.

I agree. (At high resolution) For single card power it's the GTX and Ultra (Nvidia). Multi card then it has to be 3850/3870/X2-3870 (AMD).

SLI is PIE and will make you CRY........ (sigh).

My m8 had 8800GTX in SLI and gave one to his son just at Christmas there as he thought it wasn't great. This was after about 8 months of use.

 

[Rroff]

QUAD SLI was doomed from the start - anyone should have been able to see that

Tri-SLI is never going to give amazing performance gains at best it'll be something like triple buffering - only effective in some cases and helps to keep the low end from dragging you down... but I believe it can, unlike QUAD, be utilised much more effectively on high end gaming systems... personally tho (even for high res gaming) I have no intention of going for more than 2 cards.

 

[peetee]

SLI and crossfire are the logical step forward, they will slowly become better over generations, and as manufacturing processes get smaller it will mean they can make multicore gpus that are decent. its just how things work.
Anyone remember how crap the performance gains were in a lot of cases with using motherboards that had 2 chip sockets? Point PROVEN. And GPUs are more complex, so give them a chance!

 

[Chronictank]

(A) User error
(B) Bottleneck by other parts of the system i.e. slow CPU
(C) Application written in such a way that normal SLI routines don't work with it (properly or at all)
(D) Lack of support in the drivers for specific applications that fail point C

Don't buy that to be honest, when ATi's offerings scale better on the same specs you can't blame A, B or C in most cases
The problem seems to be poor driver support, so irrespective of any of the other options your going to get poor scaling. Seeing how long this problem has existed could it be a hardware implementation problem?

 

[rubberduck]

SLI and crossfire are the logical step forward, they will slowly become better over generations, and as manufacturing processes get smaller it will mean they can make multicore gpus that are decent. its just how things work.
Anyone remember how crap the performance gains were in a lot of cases with using motherboards that had 2 chip sockets? Point PROVEN. And GPUs are more complex, so give them a chance!

Maybe. The thing is that SLI has been around for seven or eight years now and doesn't look to be improving too much over single card solutions.

 

[metalmackey]

Benching some of my games in single and SLI, i've found that on most games the highest fps goes up slightly. The interesting thing is the min fps, it seems to treble or more in SLI.