It may be the power supply, but it could also be a slightly wonky capacitor
it is interesting to me that another person with this exact motherboard I found in a usenet posting was having a similar issue in which a similar solution addressed it.
Now, that is only 2 out of several thousand motherboards they mad, but I wonder if gigabyte didn't have a bad batch.
Certainly, if stability is an issue at 7 or 5 percent is an issue, 10 percent is within spec, so I would not worry about it, but the closer to normal vcore you are the better.
10 percent is not something to freak about. Peope overvolt the vcore all the time, but usually overvolting makes things LESS stable, not more so