I was testing a install on a old HP 385 G5p which I know is not supported ( VMware hardware support list ) to try and install ESXi 6. As I was installing I got this screen below: After a quick search on VMware's website I found a KB 2087970 which describes what the PCI Info relates to in terms of the hardware which is not compatible. So for the above example I can see that those PCI Info refers to my Smart Array P400 controller. VMware will let you install and it may continue to work but the device is no longer officially supported on ESXi 6.0. So now there is a KB article to help you quickly find out what device is unsupported.