Maximum PC

Here is what I am looking at for my next build. I am mostly going to be playing some games with it. Went with the SLI graphics so I can hook up 3 displays at once. I do plan on doing some OC'ing, nothing too extreme. Couple of questions I have, the new i7 vs i5, i was told the only real difference is the HT with the i7 and most games wont take advantage of that anyway, is that true? Also, with the RAM, would getting a higher speed RAM with lower CAS give me a boost in performance? Any other general comments/concerns would be much appreciated

PCPartPicker part list: http://pcpartpicker.com/p/7ZEv

CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($229.99 @ MWave)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.90 @ NCIX US)
Motherboard: Asus P8Z77-V DELUXE ATX LGA1155 Motherboard ($264.99 @ NCIX US)
Memory: G.Skill Ripjaws Z Series 16GB (4 x 4GB) DDR3-1600 Memory ($149.99 @ Newegg)
Hard Drive: Samsung Spinpoint F4 2TB 3.5" 5400RPM Internal Hard Drive ($119.99 @ Newegg)
Hard Drive: OCZ Vertex 3 120GB 2.5" Solid State Disk ($119.99 @ NCIX US)
Video Card: EVGA GeForce GTX 550 Ti 2GB Video Card (2-Way SLI) ($139.99 @ Newegg)
Video Card: EVGA GeForce GTX 550 Ti 2GB Video Card (2-Way SLI) ($139.99 @ Newegg)
Case: Corsair 600T White Graphite ATX Mid Tower Case ($156.98 @ Amazon)
Power Supply: OCZ 750W ATX12V Power Supply ($59.99 @ Microcenter)
Optical Drive: Sony AD-7280S-0B DVD/CD Writer ($17.99 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($99.99 @ Newegg)
Total: $1529.78

Games don't take advantage of HyperThreading, let alone more than two cores. In fact, the CPU doesn't start to bottleneck performance until you get down to Core-i3/Phenom II tier processors.

Part of me is saying go with a single GTX 570, but surprisingly enough, the GTX 550 Ti in SLI outperforms it (but it leaves you limited to upgrading).

And you won't see any appreciable difference if you get faster RAM.

Thanks for the info. As for the graphics card, I was debating going with the 560 ti 448 or a 570 but deciding on SLI because I want to be able to use all 3 of my displays at once without having to power off my pc and switch cables. I also with the 550 ti in SLI because performance is roughly the same or a bit better in most games.