HP ProDesk 600 G6 SFF — low-profile PCIe 3.0 x16 slot for GPU upgrades

The ProDesk 600 G6 SFF has one low-profile PCIe 3.0 x16 slot for a dedicated graphics card. Just make sure the card is low-profile — the SFF chassis won’t take anything taller, so you’re limited to half-height options.