AMD 965 ...Memory controller or IMC
The number of controllers: 1
Memory channels: 2
Channel width (bits): 72
Supported memory: DDR2-1066, DDR3-1333
DIMMs per channel: up to 2
Maximum memory bandwidth (GB/s): 21.3
http://www.cpu-world.com/CPUs/K10/AMD-Phenom%20II%20X4%20965%20Black%20Edition%20-%20HDZ965FBK4DGM%20(HDZ965FBGMBOX).html/e So, it kinda depends on what motherboard you have at this point. In your 1st post you stated you were running DDR2 RAM, and in your 6th post you stated you bought DDR3 RAM.
Your motherboard and it's BIOS version could also be the culprit here.
/ee Generally, back in the AMD 965 days, a SET of two sticks or RAM, or a SET of 4 sticks of RAM, seemed to work better more often, than two SETS of two sticks of RAM.
i think i ran into this issue when i first made the computer years ago, and just forgot about it. Because it sounds all too familiar.