Help explaining drop in FPS on BF3

[TapWater]

I975x 3.33ghz processor
12gb ram
GTX 295
GTX 260 (physix)
1.1KW PSU

Anyway I tried out BF3 on the Alienware and this is what I found.

I could set it to Ultra settings everything turned on 1920x1200 and for about an hour it was smooth as! Maybe 45 FPS?

But after that it dropped to only 30 with occasional downward spikes to 20 maybe even 10 for a split second. As if too much action made it hesitate?

I checked temps for the video card (gtx295 and gtx260 set to physix) 295 was at about 88 degrees. PCB temp was about 77 deg. Load was around 95-97%.

Also, even though on ultra, I couldn't pick more than medium for the one called terrain quality (I think it was that one lol)

Ideas, thoughts please!

Will getting the new video card I'm talking about smooth all this out? Are temps normal?

Thanks

 

[Termie]

You're running out of VRAM. 45fps is what it would hit at ultra settings before the VRAM limit hits. 896MB per GPU is not sufficient for BF3 at those settings.

Also, you're using a DX10 card to play a DX11 game - there were known problems with that generation of Nvidia cards that limited some effects (i.e. you're not actually seeing "ultra" settings anyway) and also may impact performance negatively: http://www.tomshardware.com/reviews/battlefield-3-graphics-performance,3063-6.html

You can see in that test, which was performed at "High", that even the GTX285 SLI setup isn't scaling very well (and it has 1GB of VRAM per GPU). Your setup is going to be slower and run into more problems than the tested setup, particularly at ultra. Basically, it's not possible to run ultra on your card, performance-wise or even literally, due to it being DX10.

If you don't want to invest in a new card, I'd suggest first trying high settings instead of ultra to see if the system still slows down over a gaming session. The high setting was designed for 1GB GPUs, so that may still be too high for your card, though, and you still won't see high terrain settings, most likely.