I have the heatsink and fan installed. I finally put the whole unit in the nice case. During boot I hear the normal helicopter fan spin up, but then the fan takes a break. After about 15 minutes my unit becomes unresponsive. When picked up, it is very warm to the touch, but the fan is not running.
Is there an app that I can just switch to fan 100% or something?
There is the docs about how to setup the fan. But, the fan speed is automatically adjusted according to the temperature. After the board heats up, the fan speed will increase.
Which one images you use ?
I on VIM3_Ubuntu-server-focal_Linux-5.7-rc7_arm64_SD-USB_V0.9-20200530
I tried to edit the /boot/env.txt section to fan_mode=high and reboot and that did not make any difference.
@redairforce try to use a more newer version of firmware,
I have that same configuration firmware being built at the moment, I can share it here if you like 
Share it. I have now way of using any newer firmware than what is provided by Khadas.
You can build fresh firmware with Fenix,
there is also cloud building, all you need is a github account
and you can get firmware built within an hour,
no need of a linux computer, and you can configure your builds 
just modify the config-template.conf for build options (VIM1, VIM2, VIM3, Edge) the Linux version, distribution etc.
@redairforce you can download the firmware here:
VIM3_Ubuntu-server-focal_Linux-5.9-rc2_arm64_SD-USB_V0.9.6-201119.img.xz
cheers
I know the answer will probably be no, but any way this can build an EMMC flash version?
if you are referring to the cloud building, yes it can make eMMC version of firmware too (eMMC only for 4.9 kernel),
but with the Mainline kernel image,
just boot the firmware from an SD card or USB drive,
and enter the command sudo emmc-install and the firmware will be copied to the eMMC as well 
this version is problematic. I tried it too but a few codes were sent by the administrators. But why? Why is it getting so hot? We are asked to enter codes for a simple cooling job. The system started to shut down due to difficulty. I changed it too.