Cold starting an overclocked machine

[Redmint]

I've had this problem for a while where if I cold start my machine it wont boot up on the first few attempts and then it'll usually restore itself back to factory settings on the 4th or 5th attempt. By cold starting I mean the machine has been turned off for a while (at least a few hours) then I try to power it up.

I'm currently running a Q6600 at 3.2GHz on this mobo: http://www.gigabyte.com.tw/Support/Motherboard/BIOS_Model.aspx?ProductID=2740#anchor_os

But I had a similar problem running an E4400 on another motherboard before...

They were both perfectly stable in windows, passed all the usual stress tests etc (temps below 66C).

I was wondering if this is a known problem with overclocked machines or if it could be something to do with my power supply? I've got a Coolermaster IGreen 600W

 

[Hotwired]

My 750 failed to cold start on 4.5 when I was fiddling with it at about +5 degrees and fans on max.

It can do it when warm but if it's too cold it just can't be bothered. At least I put it down to the cold, can do 4.5 without a problem at normal or higher temps.