I currently have a GTX590 and i am going to upgrade/expand because i want more FPS on my 30" (currently drops below 60FPS often and sometimes into the early 30's)
Current system specs are
CPU- i7 2600k @4.5+ under water (depends on the season )
MB - ASUS Maximus IV Extreme Z
RAM - 16GB corsair vengence 1600MHZ c8 (4x4GB sticks)
PSU - Antec HCP1200w
GPU - GTX590
CASE - heavily modded HAF-X - take note that cooling will not be a problem, dont worry about it and post stupid comments about why i should not use either proposed scenario because of cooling limitations, let me worry about that, i will take the time to make it work.
and a dell u3011 for my main screen with 2 24" dells either side (currently being run by a HD4890)
I only game on my main screen (as you may know i cant use all 3 of my screens for 3D gaming). My question is would it be worth getting 3x GTX580(3GB) or another GTX590. And i dont mean should i upgrade, i mean which should i go with, i'm not asking you to convince me to stay with my current setup. I can probably sell my GTX590 with not too much trouble probably to a friend and not loose that much money (considering its not that old) and then the argument of, just get another and be done with it does not apply. I know that everyone says VRAM does not make that much of a difference, but i am pretty sure at the high res of the 30" that it does. also the scaling issues with Quad SLI vs TRI (i have a feeling that once its above 2 cards it does not really matter, its not going to scale that well either way and you may as well bite the bullet) take note that i cannot run quad SLI with 4 different cards.
Maybe i could get 2 x 3GB GTX580's, SLI them, and see if that enough, i assume that drivers will get better before release?? if not probably water cool them all and get a third? Also i am not after a cost assessment, i work full time and live at home (aka lots of money to burn)
I will be playing (have been playing the beta of) BF3 and have not been getting as many frames as i would like with the settings i would like (yes i have been using the beta drivers from nvidia). I have seen VRAM usage of the game reach the full 1.5GB of each GPU core, so maybe doubling that would help? Also a few other games do not run at above 60, so its not just for BF3 altho i dont really care if it is.
Another question is in regards to the layout and bandwidth of my motherboard. Can i run 2 cards in sli with one being in the very first x16 slot and the second being in the very last x16 slot, thus leaving a "double space between the cards, or enough room for another GTX590 to be placed between them). And if i do have a gap that big, what sort of bandwidth issues would arrise with running another GPU from one of the middle x16 lanes (just for my side screens, not in SLI and most porbably nvidia so i can off load physix to it and maybe get a few more frames)
adding a gtx580 would be a good option for 3 way sli, but as you said, your reaching the vram limits and it may not help all that much. It might be better to go with the 3 gb cards. Even 2 x 580 3gb would be faster as the gtx590 is effectively 2 well underclocked 580's on the same board. So 2 580's will give you more clock speed and you can get the 3gb versions.