Take those numbers with a grain of salt. I'm starting to get horrible errors on the new system. It fails Prime95 within seconds with really wrong rounding errors. I've narrowed it down to the CPU or Motherboard. I have a cheap Celeron coming tomorrow so I can hopefully figure out which one it is (unless it's a VRM issue and the Celeron doesn't hit it).
My gut says motherboard and I'm tempted to just order another and RMA this thing.
I have 4th gen i5 in one box, and 2nd gen i5 in another, I''d love better single core performance for dwarf fortress, otherwise, nothing I do really pushes the CPU too far. I'm OK with waiting for 15 minutes for a CD to encode to mp3 with lame. Beats the 20+ hours it used to take with l3enc on an old Cyrix "686" or the 10 hours with a P2, or the 12 hours with a K6.
I will keep the CPUs I have for the time being, though the 2400 is past its prime.