ALL rails should never do +-5% from the set rails or you will encounter stability issues, the neccesity to overvolt just to give the proper current, or even software corruption.
Got an Antec eh? I have a TruePower550 that only does 4.65v on the 5v rail. Sometimes cannot get past the posting.
<i><font color=red>Only an overclocker can make a computer into a convectional oven.</i></font color=red>