I recently upgraded to 6GB of RAM because my computer was running slow with 4GB when playing big games like Skyrim or World of Warcraft, but after I installed it, my comp crashed and gave me a BSOD whenever my RAM usage got high. So for the past 2 days I've been experimenting trying to figure this out. No temperature problems, the RAM isn't defective, my BIOS is up to date, I even reverted it to default settings. All the RAM cards work together but I only recieve the BSOD when I have a card in the 3rd or 4th slots in my motherboard. Could it be that those RAM slots are defective? I also recently cleaned out the dust so I've ruled that out as a possibility. At this point I'm stumped, and any help would be greatly appreciated. System Specs: Motherboard: ASUSTeK Computer INC., P5QL/EPU OS: Microsoft Windows 7 Ultimate, Service Pack 1, 64 bit Processor: Intel Core 2 Quad CPU Q8300 @ 2.5GHz Memory: 6143MB Crucial DDR2 @ 800MHz Video Card: Nvidia GeForce GTS 450 HD: 400GB Hitachi SATA 1 Also if this information helps, my last BSOD said "RT64Win7.sys Address FFFFF8800FD3DC68 base at FFFFF8800FD2C000 Datestamp 49a65b0d"