PoC we were using a Nvidia Quadro card together with APEX 2800 in an IBM x3650M4 Server. One problem we had with this configuration that we had no power cable for the Quadro card. Old Quadro cards have been known to work at degraded performance without such a cable, but this new one would not work at all.
We researched our options and found it surprisingly hard to order such a cable from our official channels. We did however find some cables on eBay & Amazon. The cable we were looking for was a PCI Express 6 pin to 8 pin Power Adapter Cable.
Luckily I discovered that I had such an unused cable in my home lab. In one of my whitebox servers I'm using a modular PSU named Coolermaster SilentPro M600 that came with such a 8-6 cable.
I also have another similar PSU, Coolermaster M2 SilentPro M620, that has a compatible cable which is a 6+2-6 cable.
Note that the card we were testing was a Quadro K4000 card which is not officially supported by VMware (or Nvidia) and the Nvidia driver for ESXi does not support it. It does however still work in a vDGA setup.