This regedit seems to have fixed it for me: http://forums.hardwarezone.com.sg/windows-8-338/awareness-thread-windows-8-memory-leak-ndu-sys-4309046.html
been playing for like 2 hours now, totally normal mem usage. before consistantly after an hour or so all my 16 gigs were used and everything lagged like crazy. Looks like it wasn't even AMD related in my case.
Open up "regedit" and go this key.
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Ndu
Change the "Start" value to 4 (to disable it).
Its a bug relating to the windows NDU.sys driver and Realtek ethernet drivers, under certain conditions it causes the "Paged Pool" memory to massively rise until its using all your memory, and it looks like BF4 triggers it somehow. If you have windows 8 and a realtek NIC than this may be your issue.
Damn brkbeatjunkie... I was going to go to a local store and buy a 780 tomorrow since they just dropped in price.... Maybe I'll hold off on that.
At least single player is cool.... NOT
