vdimm and rail, 2 multimeter w/ diffrent #

bought a 3 dollar multimeter on ebay and borrowed my cousins radioshack pocket size multimeter, when i check the rail, both show diff #.
$3.00 multimeter
3.3v = 3.6v
5.0v = 5.18
12.0 = 12.22

radioshack pocket size multimeter
3.3v = 3.590v
5.0v = 5.11
12.0 = 12.18

which one should i trust?
also the vdimm was set to 3.4(3.55v rail) but on bios it was showing 3.31(currently at 3.590v) not 3.4 any idea?

-is it ok to have 5v = 5.05 idle & 12v= 12.10 idle when o/c or should i set it to 5.0 and 12.0 idle

You've got a $3 DMM which reads .01-.07V different from another DMM--also of at best mediocre quality, and you find this somehow objectionable? What were you expecting?

And while it wouldn't appear either meter is off by much, you obviously need to trust whichever is reading the accurate number. If none of the devices are good enough for you to know which that would be, get a better voltmeter and compare readings until you know what right is. The bios readings are not trustworthy, that is the whole reason real test instruments are of consequence.