Hey, my PC seems to only want to use 50% of the installed RAM. Task manager says 2 DIMMs are installed and 8gbs are available but it doesn't use more than 4gb. I tried setting maximum memory in advanced boot options to 8096mb and my PC just BSODs saying BAD_SYSTEM_CONFIG_INFO, so i undid that. I tried running 1 stick at a time and both seem to work fine at full capacity.
UPDATE:
Full PC specs
CPU - AMD Phenom II X4 955 BE
MOBO - ASRock 970 Pro3 R2.0
RAM - Kingston 2x4gb Low Profile kit
PSU - Cooler Master Extreme 2 725w
COOLER - Antec Kuhler H20 950
GPU - Nvidia GTX 660 DirectCU II
CASE - Raidmax Super Helios
SSD - Samsung 750 120gb
HDD - 1TB Seagate Barracude
UPDATE:
Full PC specs
CPU - AMD Phenom II X4 955 BE
MOBO - ASRock 970 Pro3 R2.0
RAM - Kingston 2x4gb Low Profile kit
PSU - Cooler Master Extreme 2 725w
COOLER - Antec Kuhler H20 950
GPU - Nvidia GTX 660 DirectCU II
CASE - Raidmax Super Helios
SSD - Samsung 750 120gb
HDD - 1TB Seagate Barracude