So the other day, I saw someone had listed a Zotac GTX 1080 AMP edition on Ebay for £145, which is over £100 cheaper than any others, but there was a catch: they had listed it as not working/for parts. In the description, they said they had won it at work, but couldn't test it because they didn't have two 8-pin connectors. I knew there was a very good chance that it wouldn't work, but I decided it was worth a shot, so I decided to buy it. It came a few days later, and I plugged it in and everything seemed to be working fine: I booted to Windows, but then suddenly the display turned off and it