Core i7 990X 6-Core @ 4.6Ghz
12GB Dominator 2,000MHz DDR 3
3- GTX 580 GPU's in 3-way SLI
1500W PSU
Three Asus 24" monitors @ 5980x1080 resolution (Surround enabled)
OS on OCZ Vertex 2's in RAID 0
Programs on Dual VelociRaptors in RAID 0
Windows 7 Ultimate - All updates
Nvidia Drivers Currently Loaded = 275.50 (though 275.33 & 270.61 also have the same results)
Nvidia Surround on - CPU set as Dedicated PhysX for now - makes no difference if I set it to GPU 3 either

Initially I was pulling 85-95% GPU usage in 3-WAY SLI for all GPU's playing with ULTRA settings, DX11 and the high texture pack installed. I found that I was not getting enough juice to the GPU's so after agumenting their power feeds, I still got the same. So I overclocked the GPU's to find that I did not increase FPS, just dropped % usage down to around 75% usage on all three GPU's.

I am running 12GB of DDR3 RAM (not to mention three GTX 580's), and a Core i7 990X 6-Core CPU overclocked to 4.6GHz. Because I now see the GPU's are not being maxed out I wonder.......

Would this mean I am now limited by my CPU?
Would I realize better frame rates if I were to push the CPU to say 4.8GHz?
Is this a driver maturity issue?
A game maturity issue?
Any or none of the above?
Ideas on how I can get better frame rates?

The game play is OK, not as fluid as I would want it to be though. Considering the power of this machine, I would expect a bit higher frame rates and smoother play.

Lol... id totaly suspect its a CPU thats bottle necking you. IF you OCed your cards and their usage dropped and still getting exact same FPS then its CPU thats bottle necking. Try OCing it to 4.8 and see if theres some FPS increase. Also i dont know if games use 6 cores but do try to increase to 4.8 ghz and see if itll increase in fps.

OK then I will give that a shot - I used to have "Frank" running daily at 4.8Ghz, so it should not be an issue getting back there, may push for 4.9 or 5Ghz and see if that helps now that I have the EK block on there, seems to be cooling a tad better with the Antec Formula 7 TIM.

I got a nice fps boost yesterday when i pushed my CPU from 4.06 to 4.26, so yeah try OCing the CPU.

I found that I was not getting enough juice to the GPU's so after agumenting their power feeds, I still got the same

That doesn't happen, as I understand it. If you weren't getting enough power to those cards, the system would crash. You wouldn't just get a lower frame rate or usage on the GPUs.

If you want to find out if you've a CPU bottleneck, Alt Tap to the desktop from the game, right click on the taskbar and start task manager, go to processes tab, find Crysis2.exe, right click on it, click on "set affinity", disable 3 cores (infact, it that's a hyper threader, then disable 8 of the 'cores', just leave 3 cores running the game), then go back to performance tab. After that go back to playing the game for a few minutes. then alt tab back to the task manager and look to see if those 3 cores are maxed out.

I think you are at a slight CPU bottleneck even if you use a single 580. Tom's Hardware did a benchmark on the DX patch recently; http://www.tomshardware.co.uk/crysis-2-directx-11-performance,review-32229-8.html

It seems that the game enjoys very little scaling past the second core. About 10% going to the third and 2% using 4 cores. It uses a lot of CPU juice and anything below a decent Intel CPU will bottleneck it with a decent GPU. I'm sorry to tell you this but if you swap out for a SB@5Ghz you should see a major performance increase because of much better performance per core (but you will still have a bottleneck). Ihmo Intel needs to give us Ivy Bridge asap which should give us another 30% past the SB.

That doesn't happen, as I understand it. If you weren't getting enough power to those cards, the system would crash. You wouldn't just get a lower frame rate or usage on the GPUs.
My GPU rails are pushing 25A each for each GPU, the cards are actually pulling 28a each when they were maxed out, so I had to totally disable the forth GPU, take the power feed from that rail and feed the 6-pin inputs on the top two cards with that rail, so now the 8-pin feeds are being fed from 25a individual rails, the 6-pins are shared now on a single 25a rail and the third is being fed via 8-pin on its dedicated 25a rail and pulling the 6-pin power from an under utilized molex rail.

I was having serious system instability, crashing, and poor performance all together when I was having these power issues. After talking to Silverstone about the 1500W PSU I have, and going over everything plugged in to what rail, they suggested the above approach and it seemed to have cleared up a ton of issues I was having with running three GTX 580's in 3-WAY SLI.

If you want to find out if you've a CPU bottleneck, Alt Tap to the desktop from the game, right click on the taskbar and start task manager, go to processes tab, find Crysis2.exe, right click on it, click on "set affinity", disable 3 cores (infact, it that's a hyper threader, then disable 8 of the 'cores', just leave 3 cores running the game), then go back to performance tab. After that go back to playing the game for a few minutes. then alt tab back to the task manager and look to see if those 3 cores are maxed out.
I will give this a shot and see how it goes - thanks for this suggestion.