I have an Ibanez RG 450 (or something like that) and it has recently developed some rather nasty buzz from the 14th fret all the way to the 24th!.
It all started when I moved from guage 10's to guage 9's, it wasn't an over night thing, but it did happen quite quickly. I've adjusted the truss rod so that the string height is "with in spec" of the manual which Ibanez sent with the guitar, and this has eased the problem, but it still buzzes when doing some kick a*s Dimebag style bends!!! It is kept in a house with a fairly even room temp… any ideas??
You probably need your frets honed. You can do it yourself by using a whet stone (the kind you sharpen knives with) but I would probably take it to a guitar shop to do it for me.