Black screen. SSH in, look at dmesg, find this:
[113524.995794] NVRM: Xid (PCI:0000:07:00): 79, pid='', name=, GPU has fallen off the bus.
[113524.995798] NVRM: GPU 0000:07:00.0: GPU has fallen off the bus.
Black screen. SSH in, look at dmesg, find this:
[113524.995794] NVRM: Xid (PCI:0000:07:00): 79, pid='', name=, GPU has fallen off the bus.
[113524.995798] NVRM: GPU 0000:07:00.0: GPU has fallen off the bus.
null pid is my favorite.