Which CPU is best of these 3 oldies?

[Arkaign]

Without a doubt the P4 2.53 is the best CPU of the three. If we were talking an AXP 2500+, then it'd be a whole different ballgame (or any of the other highly oc'able AXPs).

That said, all of that stuff probably needs to go in the trash or donation imho. None of it is going to be very usable. I regularly see much better systems getting thrown away or sold for practically nothing, stuff with at least 1gb of ram, much more modern gpu, etc. Cheap broken screen notebooks also make good basic PCs. A friend picked up a Core Duo 1.66 w/2GB memory and 160gb hdd Dell notebook on CL for $100. Screen is cracked, but works fine on his monitor, plays 720p MKVs, etc.

 

[nenforcer]

I built my mom a P4 2.53Ghz 533FSB w/ HT Northwood with 4 x 256MB Rambus RDRAM dual channel on an Intel i850 (D850EMV2L) all for ~ $120 about a year and a half ago.

The Rambus RDRAM is no longer overpriced and quite cheap on eBay unless you try and get the 512MB 1066-32P modules which people think are special.

That is clearly the fastest of the three but if can tell by my sig I'm biased for the AMD platform of those era of machines.