Hardware :: Ps Change Reduces CPU Temperature?

Over the course of this year, I've been upgrading my system. Started with a mobo/CPU/RAM/video swap, going to a quad core Phenom-II 955 with 4 Gigs of RAM and an Nvidia GT-240 video card. I then dialed up the clock on that CPU, taking it to 3.415 GHz from its nominal 3.2 GHz, and I overclocked the RAM to 1704 MHz from the system default of 1333 MHz. Then I stuffed another hard drive into the box (the sixth HD in the box). Then I shove another 4 Gigs of RAM into the system, for a total of 8 Gigs.

Over this entire exercise, I have not changed the power supply. It was a Coolermaster 500 Watt supply that has served me well and faithfully. I did a careful power budget of this system and concluded that it was sucking somewhere between 420 and 450 watts at full load. Hence, my PS was very marginal. Allowing for derating as the PS aged, I figured I was really close to the edge.

However, I was having no symptoms, so I went with it. My system sits in a room where the temperature is usually around 28 C, and it would idle with a CPU temperature of 40C. Well, I started having some symptoms that were consistent with inadequate power within the last few days. I wasn't terribly surprised at that, so I didn't complain about having to go and buy a new PS. I purchased a Coolermaster GX 750 Watt supply. This is a high efficiency unit.

Since installing it a couple of hours ago, my system is idling with a CPU temperature of 36C. Mobo temp appears unchanged. No changes to BIOS, overclocking is unchanged, and nothing in the system is different except the PS. The case is an Antec P182, which puts the power supply in the bottom of the case inside its own duct. So, the motherboard and CPU don't see any heat from the PS; all of that is exhausted along its own path.

It is too soon yet for me to know if my symptoms that caused me to change the PS are gone, but the temperature change is quite striking. I have no explanation for it. Does anyone else? Temperature is being reported using the sensors command. Mandriva 2010.1 system. Edit: I am also noticing 1 to 3 degree C drops in hard drive temps, while ambient temperature in this room is constant. There are 6 drives in this box, and their temp history has been pretty constant...