asus pc probes shows my +12v is around 13v... what effects can this have?
Asus' PC Probe software is almost always inaccurate. Double check in your BIOS or with 3rd party software before you worry about it.
I agree. Asus PC Probe is not always the most accurate piece of software. Even Motherboard Monitor does not report my voltages correctly. My suggestion to you is to pick up a cheapo multimeter at RadioShack and test the voltages that way.