2xGTX 295 + Physx question about pci-e lanes

[Flanno]

So I built a rig the other day for a mate with my 295gtx's. It's the same mobo as in my sig and both these cards run at 16x speed. Mate wants a physx card but I tell him the gtx's are enough and can handle it. For instance with an i7 920 clocked to only 3.6, at 1920x1200,4xMSAA,16xAF with physx on high, average framerate in quad sli with batman is nearly 98fps. Min is around 62fps. But mate insists on a 9800gt for physx. If I go ahead and ad this, will there be any improvement or in fact will there be a drop in performance as now I would be running the 2nd GTX295 in 8x, same with physx card.

So question really is :

Is 2xGTX295 QuadSli [16x 16x] > 2xGTX295 QuadSli [16x 8x]+ 9800GT [8x]

Currently running on Dell 2408 at 1920x1200 but will be moving to Dell 3008WFP 30" soon.

 

[LoadsaMoney]

9800 GT isn't needed, as you say, the 2x 295's can handle the PhysX without the need for an extra card, and i don't think you can use 5x GPU's anyway.

 

[Flanno]

Actually you can. I am using a 9800gt at the moment for physx with 2 5870's Just have not updated sig yet.

 

[BYTEr]

Actually you can. I am using a 9800gt at the moment for physx with 2 5870's Just have not updated sig yet.

That's 3 GPU's.

 

[Flanno]

Doh..yeah you're right. But there are people over on xtremesystems and the evga forums using 2 gtx295 and a gtx 285 for physx. I think the limit is 4 gpus for rendering. The 5th is for physx so it's ok.

 

[Rroff]

Batman AA + SLI doesn't work that great either... you get maybe 20% boost over a single card at high res :S so basically most of that 295GTX setup is going to waste in that game.

 

[Flanno]

Hmmm....quad sli in the bench was maxing at over 200fps.