Though new in Linux world, I do have some experiences with this. Depending on your system, the one giving me issues is my Dell Optiplex 980, I'd say go into the BIOS and see how your SATA operation is going. Once I set mine from RAID ON to Legacy, all worked quite well and speedy.
Maybe not a direct Linux solution but if this is a cause, then who knows.
MicroWatt for me runs fast on Legacy, but Lubuntu did better with RAID on (not autodetect though).. And not sure why the change is like that, but hey, it worked. Hope it'll help you out.