PCIe Gen4 x16 Retimer Host Board, based on the PT4161L x16 PCIe 4.0 Smart Retimers from Astera Labs. Supports common clock (direct attach), hot-plug, SRNS & ***SRIS as well as bifurcation. ***Host BIOS must support SRIS natively. Only bifurcates down to the minimum lane count as the host system BIOS.
A retimer chip ‘participates’ in a link between a root complex and an endpoint and thus all basic physical layer pieces must be the same. I.E. bifurcation is only supported in the retimer to the level of the entire link. If the root complex is a x16 (no bifurcation) and the endpoint’s are 4×4 the result will be a single x4 connection. Also, the clock modes must also match throughout the entire link. If the root complex is in common clock mode then the retimer is in common clock mode and the endpoint must also be in common clock mode. If the bios can be set to support SRIS mode then the retimer must have SRIS mode FW and the endpoint must support SRIS mode. Rule of thumb: Whatever the bios on the system supports for clocking and bifurcation the retimer can support.