Hey guys, 
 
I know the whole issue of a slow frame rate and graphics is different from computer to computer but I am having a strange issue. 
 
Basically, the game runs at a full smooth frame rate on low and high settings for the first 10 or so minutes of starting the game up (via steam if anyone is interested) and over time the frame rate will slowly deteriorate eventually making the game unplayable (pressing the number keys is almost impossible during the "hacking" of electronics ).  Exiting to Windows and opening the game again resets the frame rate back to normal until it is played for a while and then the frame rate starts deteriorating.  

I haven't heard of this issue before, just constant frame rate issues. Does anyone have the same issue? 
(I can include my system details when I get home if needed, I am currently at work)

Holy hell. Never heard of that. Sounds like a memory problem to me. CPU/Graphic Cards won't do that. How much memory do you have? It sounds like there is a small memory leak somewhere.