CPU temperature control in FreeBSD

I've been using powerd in FreeBSD 8.2-RELEASE for a little more than 24 hours and have learned a lot. I posted about this installation yesterday.
First, ever since I got Conky up and running in FreeBSD, I've seen that at full load my CPU (Intel Core2Duo 6300 1.87 GHz) runs at 63-66ºC.
Now, according to information available in many posts and articles, including this, the maximum (or "critical") temperature for my processor is 61.4ºC.
So, I've been operating above the critical temperature, at least in FreeBSD.
Now this machine is about 4 years old and was a Windows box for about three of these (before I got it). The CPU is still running trouble-free, so I'm not sure if it runs this hot in Windows or in any of the other OSes I now have installed (Ubuntu and Haiku).
Nevertheless, the powerd that I enabled yesterday has made a huge difference to the processor core temperatures.
As I already reported I'm using just "-a adaptive" as my powerd_flag without any further refinement.
Now, when the machine is idling, which is what it mostly does as I have three other computers in use at the same time, the core temperatures drop to 48-52ºC which is comfortably below the critical temperature. I'll just mention an intial observation that seems to suggest that leaving a browser (I'm using Epiphany) open while idling causes processor temperature to increase by may 4-5ºC. In contrast, leaving a terminal open causes the idling temperature to increase by no more than 1-2ºC.

OK, I'll add a few comments on the GPU temperature that I see in Conky. At idle (but with screen active) the GPU (nVidia GeForce 7300 LE) runs at about 68ºC.
In normal operation, although I don't do gaming, video editing or any other high stress video stuff, GPU temperatures typically run in the 70-72ºC region.
However, although I can't find this information in nVidia's site, from other sources it seems this card can handle temperatures up to 130ºC which actually sounds enormous.
Nevertheless, it seems from reading this detailed thread about the GeForce 7300 LE card that my typical temperatures are a tad on the high side.
Recently, a nVidia card burned out in another computer here (not mine). When we took it out the fan was choked in dust so couldn't have been doing too much cooling.
So, I think I'm going to open up this box and make it dust free on the inside. Then it'll be interesting to see if operating temperatures drop.