We had a hand-me-down DEC x86 desktop at home with a Pentium II running at 233 MHz until I want to say 2002? This was around the time I learned how to build a PC since doing that was cheaper than buying one and no-one in my family had the money for that!
I saved whatever money I could to buy a 128MB stick of RAM from Staples (maybe it was 256MB?), a few other things from TigerDirect/Newegg and _this processor_. With some help from my uncle and a guide I printed from somewhere whose website started with '3D' (it was quite popular back then; I don't think it exists anymore), I got it done.
Going from 233 MHz to this was like going from walking to flying in a jet! Everything was SO MUCH F**ING FASTER. Windows XP _flew_. (The DEC barely made the minimum requirements for it, and boy did I feel it.) Trying to install Longhorn on it a year or two later brought me back into walking again, though. :D