#1
hello, i own a ibanez RG. the problem is that it has some fret buzz on the upper frets. bridge height is allmost on maximum, trus rod is as it should be. what else can i do?
#2
IF the fret buzz is between the 1st and 12th frets, then the truss rod is NOT set properly.

IF the fret buzz is above the 12th fret, then the neck may not be seated into the body properly, including at the wrong angle.

IF it is only on some strings and some frets, then it may be that the nut has issues, but that would most likely show up more at low frets. Still it could be a fret dressing issue.
#3
Fret buzz on the upper frets can be caused by a few things:

Neck angle on a bolt-neck is wrong (too high on the nut end).
The nut is cut improperly.
There's a "ski jump" where the neck meets the body (this happens more with set necks than bolts, though).

If your bridge is up as high as it can go, you need to check the neck for proper angle.