I'm pretty new at talking here. >>;; But I know what I'm talking about...

Well.
You said you JUST installed it to your system?
It's probably doing what you would do when you break in some new shoes.
It's getting used to the fan. It was testing it, and such.

It's nothing to worry about.
Try tuning down the settings once more on Crysis.
Either that, or you might have hardware faulty when you went to go install this fan.
x-x;;
Try getting a better graphics card too.
SLI yourself some GeForce 8800's.
I'll tell you man, It's gonna be a big change in your wallet. xD;;;
But well worth. >:3