sli and the impact on fps performance

greybing

Well-known member
Helo there.I know that some games are optimised to utilise sli and consequently run better but do alll games run better if 2 graphics cards aare running in sli,ie ,do the ones optimised work a lot beeter and the others work less well but still bettter than with one card.
 

pengipete

Rising Star
It would be more accurate to say that some games can't run at their maximum quality settings without using multiple GPUs. In other words, games that need SLI (or Crossfire) support it - those that don't, dont.

What SLI can't do is "improve" a game is designed to run at it's best quality settings on single GPU - unless you are talking about buying two old, under-powered cards rather than one decent, modern card in which case you should see some small improvement in fps but not a lot else and it would be cheaper and easier to buy and run a single, decent card. Don't forget that SLI is really only of value in certain specific types of game - where real-time rendering and a lot of movement (object or "camera") are involved.

If you think about it, no-one is going risk selling a game that can never be played at it's maximum settings and still maintain the necessary fps on a single, decent quaility card AND doesn't support SLI/Crossfire. They may have got away with that sort of thing a few years ago - when we had to wait a month for a magazine review - but these days, we can read reviews before buying. In recent years we've seen games developers creating products that almost force the hardware manufacturers to play catch-up but they aren't stupid enough to release a game that no-one will be able to play for six months so they positively encourage SLI/Crossfire.

The point is that SLI can't make a game "work better" - it can only allow existing features to be used that a single card of THAT specific model can't cope with on it's own. A single, higher-grade card may be able to do as much and more but SLI/Crossfire allows NVidia and AMD/ATI to sell cards after their "best-before" date at the same time as launching newer and moe powerful cards. As that also allows gamers to get improved performance by adding a cheaper card to their existing rig, everyone's happy.

Purely as a flight of fancy, I can't help wondering how long it will be before someone works out how to tap into the on-board graphics processors in the newer Intel CPUs to provide a performance boost for all graphics cards - it seems a waste to simply switch it off.

Apart from all of that, you can find the answers to all of your questions here - http://www.slizone.com/page/slizone_learn.html

I could have just posted that link at the top of the post but where'd be the fun in that:smartass:
 

greybing

Well-known member
Thankyou,all very informative.Does anyone have any suggestions as to what configuration I should use with my 2 gtx 460's,ie dedicate 1,2 graphics cards or the cpu[phenom 2 x4 965] to physX.You can allow nvidia to chhose for you also.I chose that option but I imagine the best configuration depends on the game.
 

PaulH

Bright Spark
Have physx on the second card with SLI enabled :) works best, dont let the CPU do the work.

Sli works with updated drivers, new profiles for games are attached to these new drivers, keep them up to date and you should be fine. (I have 2 x 460s and with this, i get a higher score in vantage!
 
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