I need tech head opinions cpu fans
 

Upgrading my cpu to a 2400 xp from a 1700, got fucked on my motherboard upgrade. So thats the highest I can go, I will go to hyperthreading after the new year when prices drop. What is the cpu cooling fan you would recommend ? Want to get a better one not crap.

Depends, if you're overclocking or after silence. But I recommend the SLK-800A with a low noise 80mm fan, or even the SLK-900 with an 92mm fan, that is, if your motherboard has enough space around the cpu socket for it. The SLK-900U is attached to the mobo with bolts, so it's more work involved.

I have both btw. The 800 cooling an xp1800+ and the 900 cooling a p4 2.53ghz. Great performance!

what's the deal with hyperthreading, is there a significant performance improvement?

It's not THAT significant. It basically acts as two cpu's, so you should see a performance increase on software that supports smp or when running multiple cpu intensive programs at once. As high as 30% in some cases. Or so they say..