Can you change the warning setting for the probes?
How hot is the air coming out of the power supply unit? If its not that warm then its working fine. If its real hot when the rpm is low then I would say you have a problem.
How does the system run? Any sudden shutdowns? Crashes?
What does the rpm goto when the computer has been underload for awhile. Try running a graphic intense game, convert a dvd or something to make the ps work hard and see if the fan rpms go up.
If they do then its just the warning is set to low on the probe.
I got the exact same mobo, but in asus probe II I can't see the PSU fan speed, maybe it's the way I've plugged it. Maybe you can help me get a reading and I'll be able to help you
My psu fan cable consists of two wires with a brown connector. I plugged that into the motherboard near the cpu.
By the way, the air coming from the psu is cool. The system has never crashed of froze. Mind you, I only have about 2 hours operating time since I just finished assembling it and am in the process of loading driver updates and so on.