In short:
Check for riser card/cord PCIe compatibility. Mine is PCIe 3.0 while MB and GPU are 4.0. Set PCIe in BIOS to 3.0 or whatever the lowest (slowest) PCIe version is in the chain of your devices.
In long:
A little while back I opened up a topic (in off-topic) about the occasional dreaded blank screen on boot and wake from suspend and hibernate. Force shutdown was the only way out. Even though this issue will present itself due to numerous different reasons ranging from bad memory or improperly installed memory, to misconfigured hardware and/or software, mine ended up being rather unassuming.
It ended up being the GPU riser card in the Fractal Node 202 PC case. For those who are not aware, the Node 202 is a small form factor case (Mini-ITX) in which the GPU is positioned in a way that won't allow it to connect to the motherboard directly. Rather, it connects through an extension piece called a 'riser card or cable'.
It is not faulty, nor is it improperly installed; it simply ended up being PCIe incompatible! My GPU and motherboard are PCIe 4.0 devices while the riser card is PCIe 3.0. The larger bandwidth of the devices seem to cause havoc through the riser card and results in flickering/green/blank/ displays or frozen systems.
The solution lies in the PCIe version that can be set in the BIOS. Mine was set to 'Auto'; changed it to PCIe 3.0 (to match the weakest link) and that was that!
With 'Auto' you would expect it to check for compatibility, but it is believed that the feedback signal may not even make it back (through the riser card) to the motherboard cleanly, thus causing errors.
Thought to post this on the off-chance that someone has the aforementioned issues AND has a riser card/cable installed.
