Asus P5Q-PE2 BSOD upon cold start with unsupported memory

Hi, I just recently have constructed a new PC.

Specs:
P5Q-PE2 (with updated bios)
E8400
G.skill ddr8500CL5D-4GBPI-B
HIS 4890 turbo
Vantec 500w PSU (40a on 12v)
1x Seagate 500gb
1x Seagate 1tb
Windows Vistax64 SP1

Everything was fine upon first post, but I noticed that the ram was set to ddr800. I went into bios and turned it up to it's default speed (1066mhz). When I went to install Vista, I would get errors (something.sys) and install would fail. I tried upping the voltage of the memory to 2.0v and 2.1v within it's recommended voltage with the same result. I then loaded optimized default settings for the bios and went on to install Vista without a hitch on ddr800 speeds. I decided I would try get some performance out of the ram via an overclock. I am now at 3.8ghz prime stable, 1016mhz ram speed (from ddr800), stable and no errors in memtest. Vcore at 1.3v and memory at 2.0v. If I turn the memory voltage up any higher I get regular bsod's.

The problem is that when I cold start my PC after being off for a few hours, I get blue screens. 4/5 were 0x50 errors, the other I got today was 0x3b. This happens at least once every cold start, but sometimes twice. If I get through to windows the system is stable, even with reset or another cold start (within a few minutes of being turned off). I have had no BSOD's once windows has loaded and no issues with games. If I change something in bios, like ddr speeds. The computer will reset, the fans will start spinning again and then it will die for about 3-4 seconds and then it starts up again.

If there is any other information I could give you, or any tests I could run to help troubleshoot this I will be happy to do them. Sorry if I have missed any vital information required.