Memory pushing 98% without anything open?

[fornick]

Recently, after an uptime of ~8 hours or so, my computer starts running really slow and my memory (As shown on Task Manager) starts pushing 98%. I don't have anything else open except skype and iTunes and two tabs of Firefox, but after closing everything, it says that my memory is still 95% taken up.

Before this happens though, before the 8 hour mark, my coputer runs fine, and I can have 10 tabs of Firefox open while playing BF4 and have absolutely zero problems.

I've heard that it could me be malware or something, but I've run Malwarebytes full scan more than 3 times now and it still happens.

Could it be faulty RAM? Should I contact Corsair for an RMA? Could it also be an incompatibility from my RAM to the Motherboard?

I'm running Windows 8.1
MSI Z87-G45
i5-4670k
Powercolor 7870 MYST
Corsair Vengeance 2x4GB 1600, CAS 11.
Corsair CX750M
Kingston HyperX 120GB SSD

 

[06yfz450ridr]

What process is using that much ram. I havent ever come close to using all 8gb of mine on 8.1

 

[fornick]

What process is using that much ram. I havent ever come close to using all 8gb of mine on 8.1

I don't even know. When I open task manager, and I sort it by processes, the one that consumes the most is Firefox, at around ~200 MB, give or take.