2500k/AsRock P67 Extreme4 Overclock - weird booting problem

[Arefel]

Ok, so I'm pretty new (ok well actually entirely new) to this whole overclocking malarkey, but I've been reading and researching a load of stuff online - most of it on this forum (cos it appears to be the best :shameless

Anyway, I did my OC last week and managed to get it stable at 4.6GHz (12+ hours of Prime95), after a little work. The weird thing I'm experiencing now is that when I switch the computer on, it starts to boot (i.e. fans spin up, lights come on etc.) but then it powers down before getting to the BIOS. It stays like that for about a second or two, then without me touching the power button again it just boots straight up as normal. I've double checked and it definitely doesn't do that when I reset everything to defaults...
What could be causing this, and more importantly could it be damaging anything important?

System specs are:
CPU: Core i5 2500K
MoBo: AsRock p67 Extreme4 (Pro3) (BIOS version 1.6)
RAM: 8GB G.Skill RipjawsX 1600MHz
Cooling: Zalman CNPS9900 Max
PSU: Antec TruPower 750W
Graphics: EVGA GTX570
HDD: Samsung Spinpoint F3
Case: NZXT Phantom
OS: Windows 7 Home Premium

Current BIOS settings:
CPU Ratio: 46
Internal PLL Overvoltage: Enabled
Speedstep: Enabled
Turbo: Manual
Short Duration Power Limit: 200
Long Duration Power Limit: 200
Duration Maintained: 1s
Additional Turbo Voltage: Auto
Core Current Limit: 200
BCLK: 100MHz
Spread Spectrum: Disabled

Power Saving Mode: Disabled
Vcore: 1.290V
LLC: Level 2
DRAM Voltage: Auto
PCH Voltage: 1.012V
CPU PLL Voltage: 1.857V
VTT Voltage: 1.116V
VCCSA Voltage: 0.925V

Everything in 'Advanced > CPU Config' is either Auto or Enabled, except for No-Execute Memory Protection


Any thoughts on either whay on earth that seems to happen, or more general advice on my OC would be most appreciated!
Thanks

R

 

[yetyhunter]

I have exactly the same problem and after 1 month of research I still haven't found anything to solve this issue.

 

[CPU666d1]

I can't comment on your problem,but I got some other weird booting problem from the same chipset as yours.

 

[Arefel]

Think I managed to fix it!
I had a play round the other day turning individual features on/off from the defaults to where I was before, and it looks like it was disabling the Spread Spectrum that caused it.

I'd disabled that before because it was causing some issues with the multiplier not being kept constant at 46, and instead oscillating between 41-43. Bizarrely it now doesn't seem to do that at all, so I think I'll just leave it enabled!

@yetyhunter - hope that goes some way to solving your problems too!

 

[steelbeast]

Think I managed to fix it!
I had a play round the other day turning individual features on/off from the defaults to where I was before, and it looks like it was disabling the Spread Spectrum that caused it.

I'd disabled that before because it was causing some issues with the multiplier not being kept constant at 46, and instead oscillating between 41-43. Bizarrely it now doesn't seem to do that at all, so I think I'll just leave it enabled!

@yetyhunter - hope that goes some way to solving your problems too!

I was having the same problem on both the extreme3 (RMA'd it) and extreme4 (currently own). This worked for me too. Thanks! I was able to get to 5.0Ghz @ 1.36v stable! However, my temps run around 77-78c at load, 32-33c at idle. Is that ok for 24/7 OC?