OK, so basically im pretty green with gpu overclocking, but ive managed to get my core to 850 @ 1.075 and have it run fine with all my games.   But when i try to run BF3 its a whole new ballgame.   Now while i can get BF3 to run at that speed i have issues when i go into prone... i start getting artifacts.  So i messed around with it for a bit and even running the superclocked speeds of 797core 1950 mem.  Ive tried all kinds of combinations and they all work, except when i go into prone.  All im looking to do is get my card to run at least at the superclocked speeds and be cool in my games.  Anybody have some friendly advice?
 
my build:
CPU: i5-2500K Sandy Bridge 3.3GHz
Mobo: ASUS Maximus V Gene 
Ram: G.SKILL Ripjaws X Series 8GB (2 x 4GB)
GPU: GeForce GTX 570 (Fermi) HD 2560MB
PSU: CORSAIR Professional Series Gold AX1200 
Cooling: Custom Liquid Cooling Loop
Case: Corsair Obsidian Series 800D
Mouse: Razer Naga
Gamepad: N52te
Keyboard: Razer Tarantula
Windows 7 64bit
 

I made this thread for all of us GTX 570 owners a while back a little after they first came back, there is a lot of good information on this page, check it out and post back if you don't have any luck finding what you are looking for.
 
http://www.evga.com/forums/tm.aspx?m=803526&high=post+em+up
 
Also a problem you are going to run into is heat with the HD version of the car, so pump up the fan big time using Afterburner or Precision, I have also heard from a few people the 2560mb version does not clock as well as the 1280mb, but the heat is going to be your main enemy for your HD card. BF3 is one of the more intense GPU games and I have used it to test my gpu overclock stability multiple times, if you can run BF3 with your OC you are golden. You really just need to keep your card cool, and dont be afraid of going 1.1v, I have been running two in SLI at 1.1v and 890MHz for over a year and they are rock solid. Just set up a really aggressive fan profile.

ok thanks ill look through it. 

I have a 2.56GB GTX 570 HD as well, but I didn't see a need to overclock it, it has handled just about everything I have played at max detail except for metro 2033 which I don't like as much anyway.
 
also whitnasty1 is correct on the HD version running hotter, with default fan and clocks mine gets up as high as 85C