The original CPU in my rickety home server was proving to be a little inadequate, but even the strongest supported CPU would have been such a small upgrade that I could not justify spending the money on it.
Instead, I’ve decided to do some mod-work and fit in an old (read: cheap) Xeon processor. The only issue this posed was that the Xeons that worked with my motherboard used a different socket (LGA 771) than the motherboard (LGA 775).
After doing some research I’ve found out that there’s a relatively easy way to do this, but it requires mod-stickers, a new BIOS, and phyiscally cutting the CPU socket on the motherboard.
I’ve managed to find a Xeon that was compatible for 8€, some LGA771-to-775 stickers for 2€, and… that was pretty much all that was needed for this.
The mod stickers 
The CPU
After they arrived I used a set of tweezers to apply the sticker to the CPU’s lands:
Before continuing the installation I quickly updated the BIOS to the latest version using Dell’s own utility. This posed a rather annoying issue: the executable Dell supplies is incompatible with FreeDOS, and there are no alternatives. I needed to grab an old drive, quickly install a trial version of Windows on it, and use it to flash the BIOS. This actually came in handy later; the modified BIOS with the 771 microcode was also only usable in Windows (without going through way too much trouble.)
After the update I grabbed the modified BIOS for my motherboard from here (the site might look sketchy, but it was recommended on various unrelated forums and I can confirm it’s clean), and flashed it too.
The software was now ready for the hardware to be installed. The next step was removing the old CPU and cutting the plastic tabs off from the socket. This required no special tools: I used a 3€ box cutter. (I did practice on random components of a dead laptop, but it required very little effort.)
The CPU fit nicely and the lid closed without problems. This was pretty much it: I cleaned the old thermal paste off of the heat sink, applied a new layer, and booted up to a happy BIOS screen:
This was a significant upgrade; for 10€ I have doubled the number of cores, sextupled the cache, and raised the clock speed.
