OK, so I have a few things I need to ask about in regards to modifying my oldschool machine:

1. I have a free (very huge) radiator heatsink from Sempron 2500 (left from when I was changing out the old one). Could I use it (after cutting down where needed to fit the motherboard) on an old P120 without fan and not risk overheating in process? I heard people were doing that, but want to be sure first.

2. How could I reduce the noise generated by that same machine's PSU? Frankly, its currently the loudest component in the entire PC, and is plainly annoying.

3. I found out that connecting the fans (the old two-cable ones) to 12V rather then 5V increases their RPM and thus prevents some startup problems that occured before. However, that also increases the noise produced. Is there something I could do to have precise control over the voltage feed going to them?