Hey all, I'm running an MSI P55-GD65, i5 750, 500W Seasonic PSU, HD 6870 Graphics, windows 7 64 bit and all the usual other junk. I've been running this system with 2x2Gb of Gskill ram for a couple of years with no problems. I'd always stuck the ram in slots 3 and 4 (furthest away from the CPU) because the CPU fan was mounted over 1 and 2. Worked fine. So a couple of nights ago a friend gave me 2x2GB of Corsair Vengeance RAM he had lying around to boost me up to 8GB. Unfortunately, although I've managed to get the system to see the extra 4GB of RAM, it's only using 4GB. If I go to My Computer > Properties, then I get told: Installed Memory (RAM): 8.00 GB (3.99 GB usable) Now, I've done some googling and have tried a few things already, so I'm hoping one of you can suggest some things to try. I've already tried: Every permutation of the four sticks I can think of in the four slots Removing my overclock (dropped down from 3.00 to stock, whatever that is) Upping the voltage on the RAM to 1.651V from 1.5V. Reseating the CPU cooler (some people report the RAM isn't detected due to bending, or bent CPU pins) Straightening out the one ever so slightly bent CPU pin I could find. Upgrading the BIOS from 1.00 to 1.11 Anyone got any final ideas before I just give up and live with 4GB, because I can't think of much else to try at this stage - I'm starting to think the mobo just hates me a bit. Cheers all!