LED filament lamp PSU chip thermal dissipation.

To test my theory that the high voltage linear regulator chip in the LED filament lamp was likely to be running quite hot, I reconnected the lamp to its original PSU and monitored its temperature rise with a thermal imaging camera. I also monitored the power taken by the lamp as indicated by a power-monitor plug.
The chip gets very hot, even in open air. It started regulating the current down automatically at an exterior temperature of about 70 degrees Celsius and the current/dissipation finally balanced at about 92 degrees. This was in open air in a cold workshop though, so it would probably have regulated the current a bit lower if it was in the enclosed base. As it was, the power reduced from 4W down to the lowest value of 3.5W.
What this means is that the lamp is doing the exact opposite of a compact fluorescent lamp. Instead of starting dull and getting brighter, it actually starts at full intensity, then gradually lowers its output slightly. The adjustment is imperceivable due to the smoothness and time taken.