CPU & Memory Overclock

MB: ASUS P5N-D
Proc: Core 2 Duo E8500 3.0Mhz
Mem: Corsair XMS2 DDR800 PC2 6400 4Gigs


I've been trying to figure out some of the troubles i've been having while trying to overclock my system. I did some quick research and with my board it was easy enough to get the OC going.

First i tried to take it to 3.6 and it was easily going. Everything in windows and boot were cake. After being stable for a while i took it to 3.8 and it was just as stable.

In my bios i didn't link them together and just unlinked the FSB and Memory Settings. I manually changed it from 1333 to 1600 and that put it at 3.8. I had it that way for about 2 months and it was gravy.

I wanted to take it to another level with increasing my memory now. Mhz was set as 800 in Bios and so i tried to change it by 10 Mhz and see if it would boot. It wouldn't. I wasn't able to get into windows at all. It would just freeze on windows logo on boot.

I left the memory settings and alone and wanted to see if i could reach a higher processor speed so i increased my FSB to slowly til i got to 1700 and eveything fine in windows. I noticed that being at 1700 it automatically changed my memory Mhz from 800 to 797 and that was the only it would boot into windows. I can't change the memory Mhz it'll only boot into windows if it lowers the speed.

Why does it lower the memory Mhz?

Being at 4.0 i was stable in windows for a long time no problems. Then randomly one day my computer froze in windows. I restarted it and got back into windows fine. Sometime later it froze again. I began to do research and it was leading to my memory being bad. I ran memtest and everything passed. I decided to take her back down in OC and see if it fixed any problems. When i put her back to 3.8 and loaded into windows it froze immediately every time. I tried a couple times to make sure it wasn't anything else. Once i returned it back to 4.0 it loaded into windows.

I took one stick out and ran it at 3 gigs since i was on windows 7
32 bit and only got to use 3 gigs. Same out come randomly it would freeze once a day. Sometimes it wouldn't freeze for a whole week. If i left the computer idle i'd come back and it would still be running stable. After about using it for 20 minutes it would randomly freeze.

I also tried changing VCore to make sure that it was getting enough power. Atm its at 1.40 but CPU-Z has it at 1.34 and i set my DRAM 2.1 which is Corsair's site says thats recommended.

Anyone have any ideas as what i can do to solve this freezing problem?