>Anything via Console?
All the fans are listed as OK. Not sure what other things I might check... suggestions?
> Did you blow the fans and chassis out?
Yes.
> Is it the chassis or power supply fans that are noisy?
Chassis.
> I would try cleaning the units of all dust, just in case the internal thermistors are being set off due to hot spots.
Will give them a more thorough cleaning and see if that makes any difference.
> What code version are they on?
They were all on various versions when I got them (total of four, all from the same eBay seller - had only received the first two yesterday) and all behave exactly the same way. I cleared all their configs, and installed diagnostic 6.0.0.21 and agent 6.3.6.017s; no change.
I've never had any 5650s before, so I don't know what's normal or not. I do have a lot of 5520s, and a few 5698s, all of which run this same software, and all of which just hum along at a steady RPM when running.