About 9 months ago, I started a new pc build with high hopes of being able to experience nvidia's top of the line gaming experience - ie Surround 3D. I started out with a Haf x nvidia edition case, g1 assassin mobo, i7 960 (oc to 4ghz on water), 1200w psu, 2 x evga gtx 580 (3gb editions) and 12gb corsair vengeance ram.. I also set myself up with 3 x 120hz nvidia 3d approved monitors (Benq xl2410t).. Using this setup, I was only able to achieve 15 - 20 fps in bf3 in 2d surround with settings set to ultra.. So recently I decided to purchase a 3rd gtx 580 and another 12gbs ram - also did a waterloop flush and clean etc.. Now I am still only achieving 20 - 30 fps, occasionally spiking to the 50s and 60s.. Am I missing something here? Is this the most my 4k system can handle? I purchased the 3gb editions specifically for dealing with multiple monitors and with the 3 cards, I now have the monitors all running off each different card.. I know that 1 of my cards can play on a single 24" monitor without any problems, is the SLI scaling that poor? Ive maxed out my budget and patience with this game, so is there any way to optimize gameplay using only software? Ive already given up on 3D surround (even though I get massively increased fps when playing single player campaign).. This is my first time on the forum, please help me out..
Just a guess, I have little to no experience with SLI as of now (hopefully in the future!) but running the few specs you provided through a PSU calculator (I did not include water cooling supplies as I do not know what you are using), brought the recommended wattage up towards 1000. I see your PSU is 1200w, but with other components you may be coming close to the threashold. Try finding a PSU calculator and including all your parts (the one I checked has areas to enter water cooling supplies as well PCI cards etc... which I did not enter), and make sure your PSU is up to snuff.
The article shows that adding in a third GTX 580 doesn't necessarily increase your FPS by a whole lot. You could start by running one card on one monitor, then one card in 3D. Then move on to two cards no 3D, then with 3D and so on. As soon as the results aren't as high as you would expect them to be, maybe you can better diagnose the problem. Unfortunately, this was a rather long winded post to say that I don't really have an answer, just some tips.
Yeah i dont believe that the psu is the problem.. should be overkill for what I am using it for.. As the the difference between the 3gb and 1.5gb VRAM, it should be massive! Using ultra high resolution - ie 5760 x 1200 is exactly why they made the 3gb models.. Like I said, Im just not getting the fps that I was expecting.. As for the scaling, my reseach suggest that 2 cards gives u almost double performance, whilst a third card scales somewhere near 30% extra - obviously not as good a scaling as just running 2 but 2 apparently werent enough.. Watercooling: I am using a RASA 360 kit - comes with xspc res/pump that sits in a double bay, xspc waterblock for cpu and 360mm rad in the roof that I am using 6 coolermaster sickleflow fans in push/pull configuration.. cpu is topping out at 68c after running prime for 2 hrs at a 4ghz oc..
Yeah with running the 3D, i would imagine that the extra 1.5gb of RAM would help, since everything is being rendered twice.
You said your drivers are the latest versions, but that may be the problem. I know that in the past the SLI performance for BF3 has been broken by some of nVidia's drivers, so maybe backing off to a slightly older version might help.
If worst case scenario happens to be your PSU not being enough when you calculate everything includding HDD/SSD, CPU, Optical drives, water loop and such, I would suggest selling the 3 580's and then go out and buy 2 GTX 670/680 4GB cards and you should be fine as those cards use less energy than your 580's and would even surpass your Tri-SLI setup with just 2 cards.
My single EVGA GTX 670 FTW plays BF on ultra always on 60 FPS w/ VSYNC @ 1080p.
Here is a good review on my specific card done by a member at the EVGA forums using the EVGA GTX 670 FTW 2GB cards in a surround setup.
What troubleshooting have you done? Have you tested each card individually? Ran other benches? (Unengine heaven) Updated bios on mobo? What ram speeds? How do other games run in 2d surround?
BTW when u get a chance try Max Payne 3 in 3d Surround. Its the most bada$$ game for 3d surround i have seen. Absolutely phenomenal! BF3 multiplayer i use 2d surround @ 120hz for that extra fast twitch gaming to be top of the scoreboard.