My powerMac G5's rear fans are very loud?

Question

Hi, I recently got a mint condition Dual 2.0 GHZ PowerMac G5. The computer boots perfectly, it's very fast even though it's got only 512MB of ram and so far, it has never crashed, I'm even posting my question with this computer, however, the rear fans are very loud, they're revving very quickly, and if I want to put it to sleep the fans are still very loud and it won't wake, I have to restart the machine. Does anybody how to fix it? I already reseted the PMU, I cleaned the entire computer with air, updated all the way to 10.4.11 since it had 10.4. Another thing I found was that when I opened the case to clean it, I noticed that a plug was loose, right near the ram. I have no idea where it should be connected or what is it for and I don't know if it's related with my problem, but I uploaded a picture of the cable to see if anybody knows where it should go.

Answer 1

Amed wrote:
Thank you for being quite helpful, and like you said, I checked the diagnostics on system profiler and I also got that it passed on diagnostics. I also checked my computer using techtool deluxe, it said that my CPU was working properly so I'm pretty much in doubt now. What do you think I should do next?
OK, your comment above in the singular is puzzling, and going back to your post with the System Profiler snip shows Number Of CPUs as 1.  You should see the following, if both CPUs are recognized:
Machine Name:        Power Mac G5
Machine Model:        PowerMac7,3
CPU Type:                PowerPC 970  (3.0)
Number Of CPUs:    2
CPU Speed:              2 GHz
So the question is why is one of the CPUs not showing up?  The system log listing points to a mismatch, which may simply mean that a thermal calibration needs to be run, but if the problem is only dealing with thermal calibration, both CPUs should show up in System Profiler.  Since I haven't used Tech Tool since the days of Classic Mac, I am not familiar with how it reports things like a "missing" CPU, for instance.
Not sure whether we are dealing with a truly dead CPU here, a "wrong" CPU, or what.  You can compare the EEE numbers against what should be compatible, for instance (see the DV Warehouse discussion of EEE numbers on any of the 5 CPU product pages, plus the listing of some G5 CPU modules for more information).
Finally, you can actually narrow down your model (there are two iterations with the same reported 7.3 designation) by inputting the serial number to the Chipmunk site model lookup and know for sure.