best CPU for old PC?

[Bassblaster505]

3.2gHz Pentium 4 HT VS 2.4gHz celeron, both on the 478 socket

 

[game junky]

Celerons are Pentium processors that didn't make spec, thus with a budget price tag. The Pentium hyper-threading has a higher clock speed - that's your better performance option

 

[spooky2th]

If the pentium fits the bill, use or get that one. The pentium will perform a lot better.