To confirm, different clocked NV GPU's play nicely together. I have two GTX 570's, one (Inno3d) has a stock Core of 732 with 950* on the vRam, the other (EVGA) is 797 Core with 975* vRam. Typically I'll see higher load on the slower card as you'd expect. In extreme situations, basically benchmarking, I'll see the slower card at ~99% GPU load with the faster card in the low-90's. I do generally however run both GPU's either slightly overclocked or both at the base 732/950*
* base speed in Afterburner, subject to the DDR multi of course
I've not tried it personally, but if anything was to cause a problem I'd expect it to be the vRam capacity discrepancy.
Incidentally, I game at 1920x1200 and my meagre 1.25gb of vRam still sees me playing most things flawlessly - so Crysis 2 in DX11 with the HD textures sits at a steady v-synced 60fps for the most part. Modded Skyrim (loads of HD stuff, extra detail, view distance etc) behaves much the same, apart from certain known lower-fps areas (Dragonreach steps) but even then things remain perfectly playable - and I'm dead fussy! lol.
More vRam is the future of course, but today, at standard 1080p gaming, I see no issues with 1.25gb - remember, GPU's will cache data the same way windows does, so 2.5gb
reported vRam usage on say a 3gb 7970 doesn't mean it
needs that full 2.5gb to render what it's currently asked to. As new scenes are loaded
then it might benefit from the cached textures etc. but often such scene changes in games trigger a load screen anyway. Skyrims open world attempts to be seemless when travelling outside, and my system plays it lovely.
Note: have done some testing vs. other GPU's with more vRam rendering the exact same scenes in games and the cards with more vRam always use more vRam for the exact same scene. This is again testing at 1080p resolutions, for tri-screen or 1440/1600p gaming the extra vRam helps. 3D conversely takes about 20% more GPU power, but does not have a larger vRam footprint.
Did I ramble? Sorry! lol.
Scoob.
