PCIe location for gpu and installing a second M.2 NVME SSD (HP Z240 TWR)

[Smette]

Hello everyone,

I have a 2 slot GPU currently installed in my top PCIe3 x16 port (18 on picture) of my HP Z240 workstation. I was wondering if I could also use the PCIe3 x16 (4) slot on the bottom (20 on picture), so I don't block my other available pcie ports. What does the "(4)" stand for?

I would like to free up the PCIe3 x4 slot for connecting another M.2 NVME SSD. 

Thank you! 

[DGroves]

if you had read the z240 user manual or the z240 service manual  you would have had your answer(s)

slot four is x16 mechanically, however only four PCI-E lanes are active

this means that electrically slots #19 and #20 are the same and a pci-e ssd card will perform the same speedwise n either slot

on the top x16 slot all sixteen pci-e lanes are active and is usually reserved for a video card, although some setups will use the cpu's embedded video and install pci-e x16 unique/specific card such as a raid controller or a data acquisition board to name just two possibilities