what does wired mean in 'one PCIe x16 wired x4'

A GTX 780R9 290 for example may suffer a performance hit but an R7 260GTX 750 may not The PCIe slots are rated as they are because of

View Jetson Orin Technical Specifications ; CSI Camera, 16-lane MIPI CSI-2 connector ; PCIe*, x16 PCIe slot supporting x8 PCIe Gen4 Key M slot with x4 PCIe

pcie slot configuration gen1 gen2 gen3 Next Generation Storage：1*PCIe x4 and 2*PCIe x4 Connectors EZ-Latch：PCIe x16 Slot & Connectors with Quick Release & Screwless Design

pcie gen 4 in gen 3 slot The MS-01 is equipped with a PCIe x16 slot, allowing for the installation of high-performance external GPUs, network cards, storage controllers, and other