Should I use my old T-Bird HSF as a case fan?

I'm reaplacing my old 1Ghz T-Bird with an XP (it's coming today! yay!), and I'm debating the HSF from the T-Bird as a case fan.

It fits in there perfectly, spins nice n' fast, but it's kinda loud. The main reason I wanted my old AMD fan and not the one I jacked out of an old 486 Compaq PSU is because the newer fan allows me to check the speeds and the like.

What do you think? Should I sell the 1Ghz? Or keep it and use the fan?

As I don't like noise very much I would go with the PSU fan which I suppose is a 80mm, is quieter and moves more air.
Even if you keep and use the HSF's fan you could sell the TB without the fan and with the HS.

The stock HSF on my 1.2ghz T-bird is a delta(54.5dB)... enough said.. I'm ditching this fan as soon possible(watercooling)...

Thats how I'd decide which to use