It has a single PCIe X4 slot, but the slot is open-ended — this means you can still connect an X16 card to it. Pineboards connected an AMD Radeon RX 460 GPU (the specific card appears to be made ...

PCIe x4 and x8 cards can draw up to 25W from the motherboard's slot, while x1 cards are limited to 10W unless configured as a 'full-height' or 'high-power card' to pull the aforementioned 25W.

Since the mainboard used also offered PCIe, the same card was run in a PCIe x4 slot, as well as in an x1 configuration, both with noticeably higher performance and putting the ‘why’ in ‘try’.