In this video I’m doing something I don’t say very often: I failed… I royally failed trying to get a GPU mining rig to boot and run the way it should. The build was centered around multiple NVIDIA A4000s (with an AMD Sapphire card in the mix for testing), and the “moment of truth” turned into the classic black screen/no-post headache. I started the normal way—trying to boot with everything plugged in—then backed it down to a single GPU to isolate the problem and see what would actually post. After several hours of troubleshooting, I chased the wrong theory at first. I thought it was the AMD pixel patcher situation (because running more than three AMD cards can cause weird boot issues), but that wasn’t it. What I found was even stranger: the rig would behave with one A4000, and it would even run two cards if one was the Sapphire, but the second I added another A4000 the whole thing broke—drivers, risers, M.2 expansion adapters, BIOS tweaks, Google… I tried it all. In the end I swapped the “tough gaming” motherboard out for my old reliable ASRock H81 Pro BTC and it was basically plug-and-play. The takeaway: don’t underestimate motherboard compatibility when you’re scaling GPUs, and don’t be afraid to fall back to proven mining boards. I also show the performance target I was seeing in Windows—around 65–66 MH/s at ~25 watts per A4000 with aggressive memory overclocks—then I ultimately ran the rig in Hive OS because it was simply not worth wasting more time.