I recently decided to upgrade my desktop, which was built 4 years ago, in preparation for fallout 4. Unfortunately, Installing the RAM has been an issue. To start off, I have an Asus P7P55D-E LX motherboard, Intel i5-650 3.20GHz cpu, and my original RAM is 2 sticks of 2gb g.skill DDR3 2200 (F3-17600CL9D-4GBXLD). Couldnt find that exact speed anymore, so I went slower with 1600. got 8gb of g.skill DDR3 1600 (F3-12800CL9D-8GBXL). I am running Windows 7 Ultimate 64bit. From what I read, that should have worked, but when I installed just the 2 new sticks, it wouldnt even make it to the windows loading screen. Went into the BIOS, turned off the memory remapping thing, and it would load, but would only say I have 3.5gb usable out of 8gb, where the old RAM said 4gb total with no loss. I checked to make sure there was not a max memory set, and updated BIOS. After updating BIOS, with memory remapping on, It would load until the windows startup screen appeared, then BSOD. Turn remapping off, and it would load, but would still only say 3.5gb available. Ran Memtest, and it came back with no issues found. No settings have been tweaked in BIOS, and I dont think it is the RAM itself, because that was my first thought and sent it back and got a replacement. Thanks for any suggestions on what to try, and if you need more info on my setup let me know and i will provide.