are you using a water cooler? or air cooler? if no air is going around the VRM heatsinks then they will get hot.

Switching frequency has a direct impact on the VRM heat output (higher switching frequency=higher heat), as does the power draw of Bulldozer.

Check the Vcore itself, what is it? 1.4v? at 4.5ghz, that is standard, you can try to lower that vcore, but those VRMs will get hot, very hot. especially because of the high power draw of bulldozer. When they get over 90C id start to worry, heat kills VRMs (but very high heat, like 120C+).

if youare using one of those all-in-one water coolers, try to have a fan blow over the memory and VRM.