Hi All,
 
Recently bought an Athlon 5600+ (65nm, 2.9GHz, 2MB L2) to replace my rather pedestrian-performing 4600+ (90nm, 2.4GHz, 1MB L2).
 
Problem is, I've been enjoying temps in the range of 40-45c under load on my 90nm 4600+ (good heatsink, good ventilation), I cant get the 65nm 5600+ to get below 60c IDLE   and is throttling in games/load
 
Yes, ive tried resetting the heatsink, dropping the 4600+ back in results in 40-ish temps again... Funny thing is, individual cores (I have Everest) report temps 30-35c, which is what i would have expected, but in BIOS whole CPU is at 60-65c.  
 
Trying a BIOS update tomorrow, but not sure what to do if it doesnt remedy it... Any thoughts?

The bios is probably the thing. It is probably using the voltage for the 90nm 5600. I'm not sure what voltage the 65nm 5600s need, but my 90nm part uses 1.34v. You can check the bios, and try to lower it, if your board will allow you.

Pleased to announce that, after a BIOS upgrade, my idle temps have now dropped to a much more respectable 25-30c    
 
My old BIOS obviously didnt have a clue, lol