I recently acquired several Tesla K80s. I have a system capable of running these cards so I set up some benchmarking tools to see if they are working properly. Most of the cards when installed show up as 2 devices in device manager and 2 GPUs are visible in nvidia-smi. Benchmarks on these cards work without a hitch. Some of the cards are only showing up once in device manager and nvidia-smi. I am only able to benchmark the single visible GPU. Are those cards faulty or is there something I am missing?