Hello and welcome to the forums
Is that Pentium 4 3.0Ghz ? if so then i would recommend upgrading your whole system if you want to get a good performance boost,but if you can't then since PCI-E 2.0 is backward compatible with PCI-E 1.0,you can use any card on your system, however what's your power supply and how much do you want to spend ?
P4 will bottleneck any
newer card. I agree on upgrading the whole system.
OP what are you using the computer for?