Recently, my PC began allocating very large amounts of RAM for certain system processes.
The most noticeable are svchost.exe, MsMpEng.exe, and explorer.exe.
I never had this problem before, and now I can't even play a game (Dragon Age) without noticeable frame skips.
I have run CCleaner, Malwarebytes, Microsoft Security Essentials, and Advanced SystemCare Pro [I personally have had very good experiences with ASC].
I do notice that the svchost.exe memory hog is due to the Superfetch service. When I stop the service, svchost.exe drops to 20,000 K rather than 150,000+ K. The only thing is, I have never had to do this before and I would like my PC fixed without this step.
My PC:
Windows 7 Home Premium 64-bit
ASUS M4A78-e Motherboard
AMD Phenom II X4 965 Black Edition 3.4Ghz [quad]
4GB Corsair DDR2 [had 8GB, removed faulty RAM within the past month or so]
NVidia GTX 460 Graphics
Onboard sound
SATA HD