Performance seems better. For example, it seems I can dump more tasks on
the
computer at the same time. (This sometimes froze things up.) I am still
getting
some spontaneous Internet disconnects but am now suspecting the phone
lines and
weather variations in my area.

Plus, the new power supply is quieter in steady state operation.

Well, that "Could" increase performance. I would say that putting a power
supply two times the amount then you had was the true increase of
performance. However, the freezing up problem can be caused by MANY things.
From slow processor, lack of Memory, slow video, ect. Sure, the processor
heating up, could cause it to run slow. But to be honest with you, many of
the lock ups are caused by software problems. Defragging the computer
greatly reduces "Lock-Up's" Eliminating Temp Files will frees up space, and
reducing the amount of programs running in the background (i.e. Real Player,
Messenger programs, ect), will free up resources. Eliminate any programs
from the start menu that you don't use. Not to mention any programs that
isn't in the start menu, that still start upon boot. Just because it tells
you to start at boot, don't mean you have to. It just will take longer to
start that program, but will save resources for programs that you do use
more often. Refrain from buying programs like "FreeMem" or "MemMaker".
They fake Memory, and take up more resources in the processor, not to
mention reduce hard drive space. If you want to increase Memory, then do it
the old fashion way, buy a bigger memory chip(s)

Furthermore, the cooler you can get that Processor, the better it will run.
Also, if you smoke, or have an unusually dust place, make sure you blow your
computer out with some caned air, or a compressor, regularly. Dust and
smoke can be a number one enemy on a computer, causing it to run hot, and
reducing the life of it greatly. I had one computer that had one fan in it,
and it was in the Power supply. Not to mention this was a large tower. So
I placed two more fans inside it. The power supply was blowing from the
inside out. So I put one fan in the front blowing from the outside in. And
a fan above the power supply blowing from the inside out. The effect, the
flow went from the front of the case, out the rear. I also had the heat
sink fan, blowing down on the Processor, causing the heat to blow off the
processor down to the Main board, reflecting off the Main board, and up into
the air flow, going to the back of the case.

Hope that helps,
Rick