Re: Ubuntu extremely slow on Dell D520
I can see this is a bit of an old thread but I also have a Latitude D520 and I suspect that you really need to add some RAM. The D520 has its RAM in 2 places: under the keyboard and under a plate at the back of the machine. If your RAM is only at the back it is a simple matter to swap it out for a 1 gig chip and the difference will be amazing. Pretty cheap upgrade these days as well. Don't forget that this laptop can run a 64bit OS btw.
I would however not recommend more recent releases of Ubuntu with Unity as the laptop finds this heavy going. My own D520 is currently running Slackware 14.0 with Fluxbox and runs very nicely. If you were keen to remain with Ubuntu perhaps Lubuntu?
You think that's air you're breathing now?