Thanks to the Biostar Racing B550GTA motherboard’s listing, we come to know that the Ryzen 4000 Renoir series APUs are unlikely to support PCIe 4.0 lanes. According to its specifications, it mentioned the PCIe 4.0 support is only on Ryzen 3rd Matisse.
It also states that Renoir CPUs will only support eight PCIe 3.0 lanes for its primary x16 slot.
Allocation of PCIe lanes on AMD APUs
For an APU, Renoir chips look pretty impressive on paper. These Ryzen 4000 series APUs will have up to eight-core CPUs with Vega Compute Units. The leaks gave a piece of good information about its spec. But there was really nothing about support PCIe 4.0. It is likely to have been excluded to keep power consumption to a minimum. Past APUs aren’t really known to have many PCIe 3.0 slots due to its intended purpose. Biostar did say that the motherboard supported x8 lanes with AMD Ryzen with Radeon Vega graphics but also mention depending on the CPU. It is speculative, but maybe lesser spec APUs might have lesser PCIe 3.0 lanes.
Lack of support for PCIe 4.0 SSDs
However, PCIe 4.0 bandwidth is not only applicable to the graphics card. With the onslaught of upcoming PCIe 4.0 NVMe m.2 SSDs, the future readiness of the Renoir APUs is questionable. A lot of APU designs also get integrated for notebooks. Therefore its also likely to see this applicable on AMD notebooks and mini PCs.
There has been no confirmation from AMD, yet. We’ll just have to wait until the Ryzen 4000 series APUs come out. Intel isn’t backing out of providing better on-chip graphics performance, either.
Source: Hot Hardware