After shutting down the board (using sudo shutdown in Linux), the fan on my GPU in the PCIe slot was still spinning.
I would normally expect the card’s power to be off after shutdown—then again, maybe this card is leeching power off the 5V supply that remains during poweroff?
It’s an old R5 230 2GB that was provided along with the Jupiter for some AMD graphics driver testing.
Are you powering the Jupiter through an ATX power supply or through the barrel connector?
If you’re using an ATX PSU, it is possible that the Jupiter is not properly handling the PS_ON signal line on power off, leaving the PSU fully turned on. To verify this, take a multimeter and probe one of the pins that provides +12V on the 24-pin ATX connector after you power down the system using shutdown.
EDIT: Or, alternatively, any other connector that has a +12V pin
If you’re using a barrel jack PSU, well, that could be a lot of things, and sadly I don’t currently have a Jupiter to test with, nor any GPUs on hand to reference against.