Also, the number of cores shouldn't have any impact on the Hitman engine, so changing affinity is not likely to help.

The problem in Hitman is, so to speak, hardcoded. The engine was written in a way that just doesn't agree with modern systems. I've posted a working speed fix that isn't too complicated in the other thread.

It works like this: the game detects the speed of the CPU upon startup. It has problems with modern CPU's, particularly with the mobile ones (like in netbooks/laptops).

Problem is, there is a rather small chance of it happening. We've put Hitman through our entire testlab and it never had any problems.

I've stickied the F4LL0UT's thread on basic tweaks and widescreen support. Our own support team at GOG also knows about this.