Memory Problems

Right, so i've had my PC about 4 - 5 months now and this problem is  has been reacquiring throughout.

My PC:

i7 3770k

Asus P8Z77-V PRO

8Gb Corsair Vengeance Ram

Asus ROG 7970 matrix platinum

Samsung 120Gb Evo SSD

2 Tb WD Green HDD

Corsair CX750M

My games (BF4, Skyrim, Far Cry 3, etc) always end up coming up with insufficient memory even though I have plenty. I have run them in safe mode, they last abit longer (start menu normaly) and then come up with the same message. Ive ran MemTest86 and came up with no Errors, windows is detecting the full 8Gb of memory. If any one could lend a hand within the great knowledge that is this forum i would be very grateful! 

Do you have a Windows swap file? You should check and make sure that it is not disabled. While it is controversial whether you need it or what size to have, I recommend having at least a 4GB one with that amount of RAM. A smaller one can be used with more RAM, but some programs could be unstable without one. Also download the free version of Malwarebytes and run it a few times to make sure there are no malware programs running in the background eating up RAM. Those 2 things pop out in my head first.