PCI x4 in x8 slot

Yes, it works just fine, obviously it's only work at x4 speed I would check whether the x16 slot can handle the power load of the

PCIe x4 devices are compatible with larger PCIe slots such as x8 and x16, and can be installed in these slots as well However, the bandwidth of the device is

pcie 20 x1 slot B550M DS3H ACAMD B550 Ultra Durable Motherboard with Pure Digital VRM Solution, PCIe x16 XPG GAMMIX S50 CORE PCIe Gen4 x4 2280 Solid State Drive –

pcie m2 slot PCIe cards can always operate in PCIe slots with the same or more lanes than the card For example, an x8 card can operate in a slot with x8, x16, or x32 lanes