My guess is that it was a software issue. That the slower machine, the 3.33GHz, had some programs that started when Windows started, TSRs. They will slow down a computer. Too many of them, and the wrong ones, and they will slow it down a lot.

You did not necessarily know they were there either. I have seen various programs that were loaded with the owner's knowledge or permission. Too many web sites do this. Some programs will load things that you are not aware of when you install them. Real player and Roxio products are notorious for this.

There are other issues that can make two almost identical machines run differently. A highly fragmented hard drive can make a difference, but that is not typical. Also, slower RAM makes a difference, but that is nominal. Normally, the additional RAM in the 3.33 would have also helped to make it faster, not slower.

Additional: Downloading things does NOT use RAM, it uses hard drive space. They are totally different.

I have never seen a computer that was slowed down by too small of a power supply. I have seen the work unreliably, but never slow down.