okay I'm stuck between going AMD or Intel (seems to be the case these days) I've owned both intel and amd systems, and have liked both platforms. my recent system was a dell xps studio 7100 with 1045t proc and 1gb 5770 that i picked up just to play starcraft. as the time came and past from the BF3 beta, i slowly started upgrading...and since i'm addicted to upgrading i just went berserk. so story short, here is what i have done:
corsair 600T SE (white)
h80 p/p config
2x msi 2gb 6950 xfire, shader unlocked
2x 60 gb force 3 raid 0
asus m5a88v evo
1045t oc'd 16% 3.13 ghz (tried going for 3.5 but it didn't like that too much)
now i've done some researching between sandybridge and ivy bridge, and amd 1100t and fx series procs. i know amd is cheaper and doesn't compare to the 2500k or 2600k. this is where i'm basically stuck...like i need someone to push me off the ledge so i can make a decision. i'm torn between getting the i5-2500k (or i7-2600k since its ~$50 more) with either an asrock mobo or asus mobo z68 board (x79 is just too dang expensive right now) and i want it to be ready for ivy bridge when it comes out. the other hand is going amd with the fx 8150 and a 990fx board (asus, msi, gigabyte) what i love about the amd boards is that the pci lanes are 16/16 crossfire, which i know theres like a what 3% increase from 16/4 16/8 and 16/16. (keep in mind i'm only one 24" 1080p currently, planning on scaling it across 3 of those which i know will help with the video cards and performance).
this is strictly a gaming pc as i have my work laptop to do work on, i know games nowadays only use up to 4 cores. the thing is since i'm doing this i might as well go big (not too big) and just be done and ready for the future with ivybridge or piledriver. i know some of you will say wait but dangit money is burning in my pocket and i just want to be done with upgrading for a few months and i want to be very happy with which ever decision i go with. i just need that push to get me there. please state of any bottlenecks that you might see with my current config and going with either amd or intel.
please refrain from posting intel because intel is better, blah blah blah etc etc etc.
Everything I've read says go 2500K if you want gaming performance. That said, I personally chose a 2600K and have been completely happy with it as far as gaming performance goes. Did I waste $100? Maybe...
At any rate, as a Z68/2600K owner I can tell you that you won't be dissapointed going that route. I've got a 60GB SSD that I use as a cache and it works great. I can go from a cold boot into Windows 7 in around 20 seconds, and if you repeatedly load game levels they'll be cached and the repeated loadings occur in way less time than the first load (maybe 1/3 the time).
A good full size Z68 ATX board should also give you plenty of room to run your cross-fired 6950's in. Just make sure that whatever board you get has three two spaces between the first and second PCIe slots so you'll have good cooling space. I've also got a Corsair 600T (black) with the mesh side panel with SLI GTX 560 Ti's. I'm using 4 x 120mm fans on the side as exhuast which are hooked up to the case's fan controller and run on low full time. This keeps my cards at around 75'C and 65'C for the top and bottom respectively, I would imagine your 6950's will be roughtly the same.
i've owned both amd and intel systems and hold no unfair biases. Both serve their purpose and calling one "better" than the other is meaningless.
between sandy bridge and bulldozer though, sandy bridge gives better bang for your buck (at least for gaming). The 2600k is a waste for gaming as well (games don't hyper thread).
read this article, it confirms what i've said.
also, if your worried about pcie lanes, it only makes a difference for the 6990 or 590. 6950s can be run in x8 with near zero losses (as you said). Resolution won't change this.
what resolution may change is graphic card requirements. 3x1920x1080 with two 6950s should run fine, but not at max settings on every game. My 6950 (unlocked as well) can run the most demanding games at nearly max graphics. With two screens my frame rate drops to unplayable (below 30 dips) unless i turn the settings down a lot.
so, yeah. my recommendation is to grab a 2500k and a cooler along with a decent z68 mobo.
I know how you feel, I've got money burning a hole in my pocket and I really want to go eyefinity too but in portrait mode like the 5x1 eyefinity due out soon, if its not out already. Sweet. Me, I'm waiting. Dont want to but I am. Waiting for intel to do x16/X16, pcie3, and USB3 then upgrade in one shot. One eggspensive shot. LoL