Sata transfer speed

My present motherboard is only sata 1 capable. Would I see any difference in hard drive speed if it were sata 2? I am running a 400 gb and 500 gb Segate sata.

No difference.

The sustained speed of SATA 2 capable drives is generally not in excess of SATA 1, so all you lose is a little burst speed from the buffer, and maybe the NCQ feature, though this seems to be optional in either mode.

NB. If you added a supposedly SATA 2 controller on PCI, it could well perform worse than the motherboard northbridge based controller due to PCI limitations.