CPU fan, LV 1.2GHz compared to PM 1.4GHz ?

[KentM]

I have a noisy X40 (2371-79G) with a low voltage 1.2GHz CPU. It is far more noisy than my X22, and my colleguages X24, and X31's. IBM claims the sound is within limits. I can cope with a fan, as long as the sound is soft as in my X22.

I'm planning to get a new machine. Is there a different CPU fan on the PM 1.4 X40 model comparted to the LV 1.2? and are all PM type cpu's sharing the same physicall fan design? (i.e all X31/2? as well)?

TIA
Kent