for your older system, if you wanna put a redhat distro on it, anything above 7.1 or 7.2 would be pushing it if you want a GUI, if you upped the RAM in it to at least 64 meg you would have a rather stable and good system to run redhat 7.1 or 7.2 on, im speaking from experience having 7.1 on a cyrix 333 w/ 64 meg RAM

if youre thinking of redhat 8, i run it on a p-3 667 w/ a voodoo3 PCI and 256 meg RAM, i havnt had any problems with it at all, its actually a dell optiplex GX110, if you can find one of them on eBay and want a linux box which would be cheap id recommend one as the whole system is compatable as mentioned in the redhad compatability list