So, how does it perform? Well, it took my Celeron 433 (previously running at 488) to about 84 degress (F). It allowed me to even take the 433 up to 541mHZ, running at 84-87 degress (F, 84 degress when browsing or idling, 87 when gaming). With that kind of cooling, you can really press the envelope. I imagine that if you kept your case open, that would even come down some.
This is a great fan. There's no getting around that. Then why aren't all fans built like this? Well, the price is the largest obstacle. While this unit is excellent, it'll cost you $50. Kindof steep, but all in all I definitely think it's worth it.