Update: 11/05/2013
The following day, the BSOD errors have returned, completely intermittently. Sometimes at idle, sometimes under load. So I've given up, I believe the CPU should run at default BIOS settings and frankly this makes it more unstable. Therefore, I decided to RMA the CPU. I purchased a 3770k instead, been running it now for a few hours, played some Far Cry 3, done some load testing and general PC use without issues. I think the 3570 was at fault, especially since the original 2550K never had any issues either.
ORIGINAL POST:
This may be worth a watch, I started by following this guide. Auto is apparently bad.
https://www.youtube.com/watch?v=mBEeXajbG2o&feature=youtube_gdata_player
Really great video! Thanks! After a good long watch, I believe I have fixed the stability problems completely (40 mins on OCCT without issues). I believe the fault laid primarily with the VTT being too low for my memory when running at 1.5V.
I changed the following settings after research & watching that video!:
F7 Optimised Defaults
Advanced Frequency Settings > Advanced CPU > All set to 'Auto'
Advanced Memory > X.M.P Disabled
__ System Memory Multiplier > 16.00
__ Performance Enhance > Normal
__ DRAM Timing Selectable > Quick
__ Channel A Timing, set manually to actual RAM timings (9-9-9-24) in my case.
__ Command Rate (tCMD) > 2
__ tRC > 41
Advanced Voltage Settings
__ 3D Power Control
_____VCore Loadline Calibration > Extreme
__ CPU Voltages
_____VCORE Volts > 1.125V
_____PLL > 1.875V
_____VTT > 1.125V
_____IMC > 1.120V
__ DRAM Voltage > Set manually to 1.5V
That's all from rough notes/memory so I hope that works for others with similar issues. As I said, I believe it's all to do with VTT and IMC primarily. I've read VTT should be no lower than 0.5V of DRAM Voltage to avoid stability issues. In addition, IMC should be 0.005V lower than VTT.
The issue was definitely more prominent (if not guaranteed within seconds of boot) when DRAM was set to 1600Mhz opposed to 1333Mhz. Therefore, I presume the stock Gigabyte settings were not giving the memory controller enough of a boost to support the new RAM timing.
One last thing, with my older 2550K, I had no issue running at 1600Mhz with X.M.P enabled but I don't know if it was actually running at 1600Mhz as the mobo manual says 1600Mhz is only achievable with an Ivy Bridge, NOT Sandy Bridge!?
Who knows.....I'll report back if I have any more stability issues!