I ran up my Roku Express again and ran up the hidden menu so I could monitor the temp. Within 10 mins or so it was up to almost 90degs C. (in a cool bedroom) You can see that the hardware is throttling like crazy. On mine the core frequency is bouncing about between 200Mhz and 1000Mhz. The core voltage is also dancing between 800-950mv. This looks more and more like a hardware failure to me. I suspect the components are being "cooked" due to running hot 24/7. Likewise because of the price point I doubt component quality is the best either.
I'm still running 2X Roku Premier devices at the moment. (touchwood still good so far, even though they also run hot) However as they fail will hopefully be at the point where the home TV's will be updated to "Smart-TV's" by then. Should I need another streaming device prior to that I will be looking for an alternative device manufacturer. Having said that Amazon Fire sticks are not without overheating problems. I guess they think that these devices are so cheap folk will just go out and buy another. As they say, buy cheap, buy twice.