Since nVidia cards only use the VRAM of one card when in SLI I was wondering if it's possible to get a 670 GTX 4gb and supplement it with a 670 2gb - since the VRAM of the other card won't do anything anyway.
For the record I'm aiming for 5760x1200 on BF3. The only settings I care about are FOV, mesh quality (affects viewing distance) and resolution. I don't mind low-res textures. In fact I'd be perfectly fine having wireframe soldiers running around a flat-shaded enrivonment but that's probably considered cheating.
It will really be a waste of money SLI different memory sized video cards, but if that is the only option, sure you can go for it, just be aware that you will be running only with 2GB of VRAM and maybe you need to reduce antialiasing to reduce memory usage but if you say you don't care for low-res textures, no problem, since textures sizes are one of the biggest problems for the memory...
Basically, it will work, and battlefield will run very well, but the point is that you will be wasting 2gb of memory... if you can 2x4gb go for that, even if it will cost you a little more.
He seems to be having GTX 670 2 GB already.
Anyway, 4GB doesn't make much a difference;
The 4GB -- Realistically there was not one game that we tested that could benefit from the two extra GB's of graphics memory. Even at 2560x1600 (which is a massive 4 Mpixels resolution) there was just no measurable difference.
Now the setup could benefit from triple monitor setups at 5760x1080 (which is a 6 Mpixels resolution), but even there I doubt if 4 GB is really something you'd need to spend money on.
Actually I have an 8800GT. Let me tell you, playing BF3 on this rig is nothing short of painful.
I don't have a 670 yet and it'll probably be a few months before I can buy ONE of those babies. I don't see that as a problem though as there are no 4gb 670 cards available in my eastern european country at this moment.
I'd like to game on three 1920x1200 monitors - including bezel compensation that's over 7 megapixels.