Might be that some data got corrupted during update processes. You should repair your BF3 installation first:
At first, download and install the latest version of Origin at www.origin.com/download (and make sure you have your Origin account ready as well).
Close the origin client and go directly to you origin folder C:\Program Files\Origin Games. Run the origin.exe in this folder with a rightclick -> run as administrator. Rightclick on your BF3 icon in "My Games" and choose "Repair Install".
Are you running several other applications while playing BF3? Even if you have high speed RAM, it could produce RAM leaks if you have several other applications open while BF3. Do you have this spikes only on Endgame maps or on every BF3 ladder?
Cheers
Basti
