I am running Sparky-Lxde on this laptop and the performance is outstanding. I do disagree a bit though because different distros sometimes are running a different kernel and/or xorg version and can affect performance. I was running MX-14 on this laptop and when the kernel was updated to 3.16 from 3.14 my system performance got hosed. However, with my Sparky system the performance increased with the kernel update to 3.16. And yes, there are more background processes running on the Mint system. I'm not all that fond of Mint, I don't really even remember why I installed it but the kids don't complain. I still want to give Sparky a try on that P4, if I can squeak a little better performance with Sparky the kids will be happy.
Thanks for the comments.