I have a Volcano 12 Fan
The fan is supposed to operate at 5500 RPM according to the spec, but
speedfan, mbm 5 and the bios all read a speed of 2800 RPM.
Which info should I trust ?
(Athlon 2800 on a ASUS A7V8X-X)
Does that board have Asus' Q-fan feature?
Most people consider that a desireable feature, reduces CPU fan speed and
increases as CPU temp exceeds 50C. Frankly, i'd hate to have any system
with a fan running at 5500 RPM, it's just too noisey and with some fans
not having the greatest bearings, they may be one of the first failure
points in the system at such a (relatively) high RPM, in addition to
depositing more dust in the 'sink.
If you want full fan speed (and noise) ALL the time, check the bios setup
for Q-fan setting, and/or try a different motherboard fan header.
However, if you use a different fan header, be sure that header stays
powered in power management modes you may use... in the past some fan
headers shut off in certain power management modes, which can obviously be
a problem.