I had a P3 500MHz with a i810, bought a 160GB and was using 40+160GB HDDs.
Gives probs during XP install, detected HDD as only 112 odd GB, you have to use Intel application accelerator else all partitions wont be detected. Dont know if 250GB HDDs will work.
If the HDD is not detected at its full capacity, buy a add-on PCI IDE or SATA card which will do the job, i’ll suggest u go for the SATA PCI Card [Atleast your HDD will be Future Proof]
Consider this case: If i go for a 500 / 750 gb one & not use the 40 gb in my above config, does the PSU support it or do i need to go for a separate PSU?