Hello, I recently downloaded Painkiller demo to show my friend the game and I noticed that it runs much faster than it should. I've been searching over the internet and found out that there were people that had this issue but all of them have AMD Dual Core processor for which they have been recommended to use AMD fix of some kind but I have following specs of my laptop:
Windows 7 Home Premium 64bit
Intel Core 2 Duo T6600 2,2 GHz
ATI Mobility Radeon HD 4650

Any ideas? Thx a lot :-)

First fix attempts should be to set core affinity to just your primary core (core 0). Also try various compatibility modes and options using the shortcut options.

I set affinity to core 0 but doesn't seem to change anything, I also ran the game using windows Vista compatibility modes getting same result. When using XP compatibility mode menu seems to be running correctly but when I start the game it is still about two times faster.

I'm assuming you are trying the first singleplayer demo. The issue I noticed is that the game doesn't seem to have an internal timer other than the processor clock (most games set a tick rate independent of processor speed). This was fixed in a later engine version, and you can test that out with the MP demo or SP demo 3 (SP demo 2 might as well, I haven't tried), as those feature an engine update which better regulates the game speed.

Mind you, playing at the turbo speed can be a neat challenge.

I ran into this issue when I had an SLI setup.
If I disabled SLI, the game ran fine.
If I enabled SLI, it ran at 10x the speed.