Very old hardware question

Hey Tom's

So have recently come into acquisition of 2 different processors and motherboards. Someone gave me a free HP Pavilion a610e, which has the AMD Athlon 2500+ single core. I also have a MSI 775 motherboard with a Pentium 4 at 3.2GHz (which I am trying to fix at the moment).

Would anyone be able to tell me which one is faster? I'm thinking the Pentium 4 is the faster pick, since its got a higher clock speed, but I am not an expert in older/vintage hardware.

Also, is the Athlon 2500+ faster than an older 478 Pentium at 2.4GHz?

Furthermore, is this Pavilion even worth keeping? I could gut the card reader for my main computer, and use a couple other parts, but I hate it when older full computers go to waste because they are too slow. I could really use the hard drive though.

The uses of these computers would be for student work and for light gaming, such as Killing Floor and League of Legends, and other low end games.

Thanks,
-Josh