I’m loving the U4 except for Fan Noise. I did some tests running at each brightness level for 20 mins with ambient temps of 19c and measuring expelled air temps (digital thermometer probe held next to the air vent):
Presentation mode 29c
Normal Node 29c
Night Mode 27c
Eco Mode (hidden) 26c
So there’s a bit of thermal headroom to drop the fan speed for night mode and it would also be great to enable the super-eco mode with an even lower fan speed. Super-eco mode (accessed from the hidden android menu) is bright enough for me in a small dark room