First of all, one should never use tape to secure a CPU fan onto a CPU. Fortunately, most CPU these days are programmed to shut off when the CPU is about to self destruct.
Intel's new Core 2 Duo processors such as the Yorkfield or Wolfdale can take heat up to 100 celsius without destroying itself; but the fact of the matter is that the CPU fan MUST be secured onto the CPU in order to cool it properly.
If you had the motherboard alone and out of the case you should be able to pick the entire motherboard up by the CPU fan without it coming off, otherwise it isn't secure.
Personally, my E8400 Wolfdale stays at a nice 26 degrees Celsius while idle and usually about 32 degrees celsius while working.
A game like Crysis actually will perform just fine on a Core 2 Duo running at 2.6GHz. What you need is a high performance PCI-E 2.0 card, such as the 9800GTX+ 200 series Nvidia card and very fast DDRAM (I'm talking upwards of 1066MHz, which is what I use)
I love the Butterfly fan, which is made for LGA 775 sockets, which support the Core 2 Duo. It keeps my CPU very cool. You have a Kentsfield, quad processor, which also supports LGA 775 sockets, and thus you can use a butterfly.
If you want a really good deal on computers components visit NewEgg, they are the best!
I hope this helps.