3.21GB usable when installed single channel, but it comes 7.21GB usable with dual channel.

MooseKhaleel

Honorable
Nov 26, 2013
3
0
10,510
excuse me, i have a problem with my memory. it's new, though. my motherboard has just two slot of memory. (Gigabyte f2a55m-ds2) at the first time i installed the memory (kingston hyperx blu 2x4GB) it just shows 7.21GB usable, so i try to check my RAM one by one to check which is just provide 3.21GB usable. but both of them shows 3.21 GB usable in single channel. when i opened resource monitor, it says 810MB is hardware reserved. my OS is windows 7 ultimate 64-bit. i've tried to uncheck the settings in msconfig too. and i checked in BIOS it has installed 8GB. . i can't even find memory remapping in my BIOS. i've been searching for so long and got nothing.

i noticed the slot memory on the motherboard just provide 1.5v, but my RAM needs 1.65v. is this the problem ?? or is it because i use a APU which has discrete graphics ?? so what should i do in order to free the rest of the memory ??

i hope all of you can help. thank you.

this is my complete specifications :
gigabyte f2a55m-ds2
kingston hyperx blu 1600mhz 2x4GB
a8 6600k 3.9 GHz
seagate 1tb