It went a lot quicker than I thought it would: the new processor and motherboard are in the server now, and everything works fine.

The website will be quicker from now on. On the bottom of this page (in a very small font) you can read the page-generation time. For the frontpage it changed from 1,5 seconds to about 0,5 second.

From now on the main bottle-neck will be the bandwidth of the ADSL connection and not so much the server. Anyway, I consider it a big improvement. Thank you Edo!