Yeah, u did read right
I got an old GPU from a friend (RX 480) and wanted to try it out.
Once I built it in and turned on the pc, the pc turned off within a second and little smoke came out of the back (gpu/mainboard)
It also did smell burned.
I immediately pulled out the power adapter and took the GPU out.
I then turned on the pc again without gpu, worked well. I did let stay it turned on with no gpu for about 5 minutes to see if there will be any issues - none.
Then I built in my GPU, turned it on again - worked fine.
I did a CPU, RAM and GPU stress test - everything fine and no smoke/burned smell.
Is there anything I have to worry about? I did a dumb mistake - i really do hope that I dont have to replace any hardware tho