[email protected] and good temps, perfect. Seems to be the sweet spot for those chips mostly.
That's still ok, 1.4v is generally the safe upper limit.
But the difference from 4.6 to 4.8 isn't really noticeable or worth it IMO.
keep it at 4.8ghz,temps/volts are fine
EDIT: your vid seems high though at 1.512v? seems to be drooping a lot
it means that's your actual voltage but due to vdroop under load its using 1.36v aslong as it doesn't spike to 1.5v when idle ect
you have all powersaving enabled? using offset
Temps at 4.8 appear well under control I'd be trying to see if this isn't one of the golden chips that can do 5GHz. I don't really buy into the idea that the difference between 4.6 and 4.8 isn't noticeable so you shouldn't bother. Surely the whole idea behind overclocking is to get the best performance out of the chip. If you follow the 200MHz doesn't make a difference argument to its logical conclusion you'd end up underclocking. It looks like your brother has a really great chip there why not get it running at it's full potential?
you'll be ok
I wouldn't run above 1.4v 24/7,it could degrade the CPU
Offset will only give you lower idle temps/voltages