My XTI4000's fan runs fast (at its highest speed) all of the time......
(continued)....although the amp seems to work well.
I own four xti4000's in total and the other three have fans that vary speed. The unit in question's fan did "vary speed" when I first bought it...it just started running at full speed a couple of years ago.
The units that I have are first generation and all have had the ribbon cable / front panel upgrade.
Other than the fan noise, the unit seems to run well.... I use it in one of my long-throw outdoor racks thus the fan noise is not an issue..
Should I be concerned??