|The bios usually pays no heed to the rpm of a case fan. |
It's a lot more likely the message is about the CPU fan - the most important fan in the SYSTEM.
Go into the bios Setup. There may be a setting for the minimum rpm of the cpu fan, and a lot less likely, for the fans connected to other 3 pin fan headers on the mboard.
If an rpm goes below that minimum, the bios generates a warning message.
If the minimum rpm for the cpu fan is higher that it's presently spinning, either the bearings in the CPU fan are failing, or it's extremely filthy and can no longer spin as fast as it should because of that.
If there is no minumum rpm setting like that, the cpu fan is probably spinning slower than bios defaults expect . In that case, it doesn't matter whether the cpu fan is used or new, you have to install one that spins faster to stop the error message.
1700 rpm sounds too slow for a cpu fan, but it depends on it's diameter - usually the larger diameter the slower it spins.
If you don't see an rpm rating on it, tell us the brand, diameter of the blade, and model if that's there.
I was unable to find the rated rpm for the Foxconn model pv902512L, but 700rpm does sound way too slow.
".... 92mm, 0.16a Dc 12v"
Unplug the case/power supply.
Power off your monitor.
Open up the case by removing the left panel as seen when you're looking at the front of the case.
Take a look at the labels on the CPU fan and the case fan. Sometimes it's rated rpm is printed on it.
If the cpu fan/heatsink has mung (dust, lint, etc.) on it, clean it off, but DO NOT use a vaccuum cleaner to do that (they produce a tremendous amount of static electricity when running, and anything connected to them can discharge that to your components) - use canned air, or an air nozzle if you have access to an air compressor, or an artist's brush that can be used in small spaces, etc. It may be difficult to clean the top of the heatsink under the cpu fan - the most likely place to have mung on it - and the bottom side of the cpu fan blades unless you remove the fan. If you have a case fan, clean that too if it needs it.
With the cover still off, restore the AC power, start the computer and make sure the cpu fan spins - if it doesn't spin, if you're sure the power supply is working okay, don't use the computer until you have replaced it.
If it spins too slowly, and/or if it makes rattling or screeching noises, most likely to be noticed when the computer has cooled to room temp, has not been used for a while, and then is started up, the cpu fan's bearings are failing - replace it as soon as you can.