HSF Fan Speed Dying (but fan is new)

[wlcna]

My HSF fan runs 1000 rpms lower than it should and i can't figure out why.
I replaced it within the last few months because I had the same problem with
the prior fan and thought it was the fan that was going out. Now it's a
couple months after the new one has gone in and I've just noticed that now
its speed as well is in the toilet, at just a touch higher rate than the fan
I took out.

When the new fan originally went in, it ran at the normal speed.

The lower speed results in my cpu temp running 4-5 degrees hotter, which I
really hate, and it just gets hotter as time goes on and the fan speed keeps
declining.

I clean the inside of the case whenever I go in there and used a pointy
vacuum to suck as much crap out of the heatsink when I replaced the fan, and
it doesn't seem *that* dirty in there.

Any ideas? More cleaning? Taking out heatsink completely and cleaning it
with water or something?

 

[Anon]

My HSF fan runs 1000 rpms lower than it should and i can't figure out why.
I replaced it within the last few months because I had the same problem with
the prior fan and thought it was the fan that was going out. Now it's a
couple months after the new one has gone in and I've just noticed that now
its speed as well is in the toilet, at just a touch higher rate than the fan
I took out.

When the new fan originally went in, it ran at the normal speed.

The lower speed results in my cpu temp running 4-5 degrees hotter, which I
really hate, and it just gets hotter as time goes on and the fan speed keeps
declining.

I clean the inside of the case whenever I go in there and used a pointy
vacuum to suck as much crap out of the heatsink when I replaced the fan, and
it doesn't seem *that* dirty in there.

Any ideas? More cleaning? Taking out heatsink completely and cleaning it
with water or something?

Many motherboards have built in fan controls, so the motherboard might be
programmed (in BIOS) to turn the fan speed down when not needed. 4-5
degrees hotter is not bad, unless it was borderline to begin with, so the
logic of the BIOS might be to save your ears in exchange for a CPU that is
slightly warmer.

But if this isn't plugged into the motherboard or another fan controller,
you'd have to start suspecting a bad motherboard or possibly bad power
supply. It's more likely to be a bad motherboard if the ONLY symptom you
are seeing is slower than usual fan speed on a fan plugged into the
motherboard. That's because if the power supply is dropping voltage enough
to significantly slow the fan by itself, you would likely not have a working
system at all, and the fan would be the least of your concerns. -Dave