[swam4]

Hi. My PC has been running fine for 6 months however, 2 weeks ago I began getting Blue screens whenever i start my computer after about 10s-1minute of being in Vista (x64 Ultimate). THE BSOD are usually PAGE_FAULT_IN_NONPAGED_AREA or IRQL_NOT_LESS_OR_EQUAL and have had system_service_exemption and recently Modification of system code or a critical data structure was detected. After the restart the pc generally works ok. Recently programs have crashed more frequently with a BSOD (usually non streesful apps) so I ran memtest.

Memtest found numerous errors. I also ran memtest86+ (v2.01) which also found many errors (esp during test 5). I have 4gb of ram (2 x 1gb of corsair, and 2 x 1gb of Geil 6400) I began by lowering memory speeds to 667, lower timings to 5-5-518-2T and played with higher and lower Ram voltages (1.8-2.2V) and diff timings including TRC and TRFC. I recieved no errors with each stick individually (tested for 9hours each and tested a stick in each slot). I also get errors with just the 2 corsair in slots A1 and B1 or A1 A2. I reduced my CPU speed and enabled virtualization tech with no effect. I reinstalled vista with vista SP1. I heatsinked southbridge and added a fan to northbridge. I also changed the bios to the latest 0901 and then back down to 0608 and 0703 (all had memory errors). I have also unistalled norton 360, nvidia display drivers (8800GTS 640mb) and creative audio drivers for my X-fi.

I have spoken to ASUS who suggested going back to 0901 bios and lower LDT frequency to 4x from 5x (also tried 1x and with diff ram voltages). Lead to same, if not more errors. Anything else I can do would be very much appreciated??

RAM timings:
5-5-5-18 2T @ 800HMz 2.1V

Thanks for any help you can offer, getting very frustrated now!
Sam