Got one (from lambda-tek), installed in a Supermicro SYS-5028D-T4NT running esxi 6.5.
At least with the default BIOS settings, only the top slot seems to be recognized by esxi.
I have tested with and without the motherboard M.2 slot populated, tried some simple PCI BIOS settings, and I did power off the machine between tries in order to bypass the Samsung 960 incompatibility bug with that motherboard, but no difference.
Maybe I tested with the wrong BIOS settings. There is a "bifurcation" option in the BIOS, but there is a lot of other stuff, and I didn't feel like testing all possible permutations blindly.
In absence of a hard immediate need for more slots, I let it drop for now.
Maybe someone here knows how to ask Supermicro why that is or knows how to enable the bottom slot?
So I have not been able to test if this is a controller-equipped pci board that will allow me to get full bandwidth of both slots, but I can confirm that:
* the top slots works
* at a good speed
* and the 960 in it stays rather cool (better than the 950 I have on-board, even with the copper heatsink I added to it), so the airflow is good.