Best pci modem I have used if rated "price vs performance" is the USR 56K Voice Hardware PCI 2976 (OEM version) ........ $58. at a local pc shop (no shipping or tax).
I don't buy that Win-modem rational, ......... even if recommended on this web site ............... ?
Maybe it's fine for a back-up, if you have a cable or DSL connection, but not for dial-up use only!
I'm using a 1.2G cpu (which should be more than enough) ........ and I don't like skips or pauses in my music if I'm jamming to some tunes and web-surfing at the same time!