I haven't heard of any CPU-related issues, but the current patches are sort of in a "two steps forward, one step back" tango. Some major thing would get fixed that breaks a myriad of smaller things, which would get fixed in the next patch that would then break some other minor things...

It's also taken a frustratingly long time to patch major game-breaking issues - the main one I kept running into was getting the "accept revive yes/no?" prompt when you die, which you can then not get out of short of quitting the game entirely.

They also managed to break SLI support completely during a recent patch. Like, completely. SLI users would have their screens turn into a flashing disco-tron.

Client crashes are still an issue, but a lot less common than before. Server crashes are likewise still an issue, but a lot less common than before. The general stability of Battlelog seems improved also - right now the general crashi-ness situation resembles what the game should have looked like at launch.

Been quite active in BF4 since liking BF3 enough to update. Only a handful of crashes, most of which during apeshit insane scenarios. Resource usage by the engine feels far more efficient than say, GTA4. My moderate laptop with dedicated graphics card can handle the game swimmingly at medium-low settings.

No third party "helper" apps or non-standard or beta drivers, and a few background applications running clogging up some potential memory resources wanted by the game.