|"Just so you know i have tested each ram stick and they are all fine"|
Meaning what? You ran memtest86 (or Windows Memory Diagnostic) on each stick individually, then as a group & no errors where found?
"I think it should be pointed out that my PSU is 900W"
Never base a PSU on wattage. Manufacturers can juggle the numbers to come up with a 900W rating. Having adequate amperage is what's important, especially on the +12v rail. And it's generally best to get a PSU that has a single +12v rail with a high amperage rating rather than a unit with multiple +12v rails. If your unit has the multi-rail design, it's important to "hand balance" the compnants so that one +12v rail isn't being overloaded while another sits idle. Also, the PSU should be built using high quality components. Obviously the hardware is difiicult to determine so it's best to stick with brand names that have a good reputation.
Does GW = Great Wall?
Have you monitored your CPU temp to make sure it's not overheating?