2 GTX295 Quad Sli plus GTX 285 for physx

[Flanno]

Am currently running 2 GTX295's in quad sli. My brother has offered me his GTX285 for free as he is going ATI soon. Would it be possible to use this for just Physx ? So is quad sli plus physx possible ?

 

[Flanno]

Thanks for the advice lads. I'll give it a go to see if it works anyway. I assume more decent games run physx now. Last time I looked, twas when Aegia were trying to make a go of it.

By the way, I assume the Corsair HX1000w will be up to the job. Running a 920 @ 4ghz, Corsair H50, 2 velocirpators and a 2tb wd green for storage.

 

[Flanno]

I doubt you'd see a difference with QUAD SLI unless you were using a hydra multi-GPU board... 4 card scaling with SLI is inefficent enough that you have masses of headroom physx can use without impacting directly on rendering performance...

I thought on X58 mainstream boards and mainstream Nvidia cards, you had to dedicate a card for physx directly or else it would just use the cpu. So even if there is headroom left over with Quad SLI, physx wont work on either card unless I just use 1 295 for gaming and assign the other to physx. Which wastes a 295.

I'm also thinking that all X58 mobos that don't have the NF200 chips or chips, will be limited to 32x lanes. So I'll end up with 16x for 1st 295, 8x and 8x for 2nd 295 and whatever I use for physx. Would I see any performance drop in games that don't use physx then, given I currently run at 16x,16x for both 295's, or has the 2nd pci-e slot not been saturated beyond 8x for current games anyway ?

 

[Flanno]

Thanks again lads. Didn't realise in the control panel you could enable physx and it work on the main gpu's.

As for why I'd want to do it. Cause the card is free and I don't want to sell it

But I take everyones point on heat, electricity and the 1kw psu maybe being tight.

 

[Flanno]

bare in mind the NF200 chip usually has x16 lanes into it and then splits that to 2 lots of x16 lanes out... and switches... so its not like having true dual x16 lanes - but for SLI/multi GPU it works great as the NF200 chip can upload data to both cards at the same time and shortcut transactions between the cards... which in theory means you get better gains than normal with SLI tho from my testing it looks like only 5-10% better tops.

yeah..I was looking at the asus supercomputer board which has dual NF200 chips opposed to the one on the EVGA classified. Too expensive though.

 

[Flanno]

I was thinking of that also. This supercomputer board from asus is able to support 4 4870x2's in 16x mode. It has 64 lanes. Though I'm not sure the drivers will handle it.