EVGA GeForce GTX 570 HD 2560MB in SLI and overclocking

[Mandilloran]

I have just purchased a new system which will incluse the norms of i7 2600k CPU with liquid cooling, 16 gigs of 1600 Ram, Cooler Master HAF 932 Advanced Full Tower ATX Case, Corsair Professional Series Gold AX1200 Fully-Modular 1200 Watt 80 PLUS Gold Certified Power Supply and a pair of EVGA GTX 570 HD 2560MB video cards.I am waiting for the system to be put together and will be a few days before I see it but looking forward to gaming on it.My question is about this card and overclocking it as well as its over all performance in SLI. For better or worse I have gone with it and my thoughts ere I would rather over clock this card to safe comfortable levels and have 2560 MB vram instead of a factory overclocked card with say 1280 MB. Anyone play with this card in SLI or overclocking it and qhat levels have you used it at when overclocked if?