This is my first time posting, I tried to verify this specific issue hadn't been asked as well as tried to make sure I follow all guidelines, forgive me if I missed any!
To start, here are my system specs, I can add more details if needed:
Windows 7 Home Premium SP1 64bit
Intel Core 2 Quad Q9550 CPU
Antec 900 case w/5 120mm Tri-cool case fans & 1 200mm Tri-cool)
Asus Formula Maximus X38 motherboard
OCZ Reaper HPC PC2-8500 RAM (up til recently 8gb)
EVGA GTX 470
850w Thermaltake black widow PSU
500gb Seagate HD, 1.5tb WD HD
Up until recently, I was able to run 8gb of the OCZ Reaper RAM just fine, until recently my system started blue screening. Long story short, I've determined the issue is the processor (swapped out the CPU with an E8400 no issues, swapped out the motherboard with a Gigabyte GA-EP45-UD3P, swapped out the GPU with a GTX 285).
When I run Memtest using the processor, it passes tests in each slot using 4gb or less of RAM, whether it be 4x1gb, 1x2gb + 2x1gb, 4x512mb, etc. As soon as I put in more then 4gb of RAM, on the Memtest where it tests RAM from 4gb-6gb, it freezes - not errors out, but freezes the program, to where I have to hard shut down. Again, this only happens on this Q9550 CPU, none of the other CPU's I have (E6300, E6400, E8400, Q6600, Q9300) have this issue using the exact same RAM on the exact same motherboard (with the exact same GPU, HSF, PSU, etc).
Does anyone have any recommendations, or is this chip destined to only be used on a 4gb system (where it's ROCK SOLID)?
Thank you for your time & recommendations!
If you already tried other processors and all of them are working fine with the same board and RAM you may isolate the problem already, even though you can give it a try updating the BIOS to the latest versions.