OS X 10.9.3 lag

Question

I just installed OS X 10.9.3 from the App Store.
I'm in the middle of playing Bioshock Infinite, and now the game is horribly laggy. It was working fine before the update. Any ideas?
I've also found the system itself to sometimes be laggy/slower.
Unfortunately, I do not have a recent enough backup for restoring to be an option....
Any ideas? Thanks..
2011 MacBook Pro 13"
  Model Name:          MacBook Pro
  Model Identifier:          MacBookPro8,1
  Processor Name:          Intel Core i5
  Processor Speed:          2.3 GHz
  Number of Processors:          1
  Total Number of Cores:          2
  L2 Cache (per Core):          256 KB
  L3 Cache:          3 MB
  Memory:          16 GB
  Chipset Model:          Intel HD Graphics 3000
  Type:          GPU
  Bus:          Built-In
  VRAM (Total):          512 MB
  VRAM (Dynamic, Max):          10
  Vendor:          Intel (0x8086)

Answer 1

my early MP 2009 is pretty laggy after upgrading to 10.9.3 without playing anything. Switching deskopts, opening/closing folders, moving windows and like that is really slow and stuttering with a nice ghostery effect.
Nothing helped yet, the graphic drivers are just, well, not really good.
too bad that apple can't realease anything that will work, with every update something else is broken...