Redshift: PCIe Riser Cables and GPU Stability

A PCIe riser cable connects a graphics card to the motherboard while allowing the card to be installed elsewhere in the case. This can help accommodate larger cards or multiple GPUs, but depending on the hardware combination and installation, the connection can sometimes affect stability or GPU detection.

If Redshift freezes or stops detecting your GPUs, testing without the riser might help narrow down the cause. These symptoms can have other causes, so they do not confirm a riser issue on their own.

Test with a direct connection

1. Shut down the computer and disconnect power before changing hardware.
2. Follow your hardware manufacturer’s instructions to connect one GPU directly to the motherboard, without the riser.
3. Repeat the operation that previously failed. Where possible, compare the same GPU, project and settings with and without the riser.

If the direct connection is stable, the riser connection may be contributing to the issue. If the problem continues, further troubleshooting is needed.

Please note: 

Selecting only one GPU in Redshift does not bypass its riser cable. If you are unsure how to change the connection, please ask your system builder for assistance.

PCIe generation and BIOS settings: Some systems may require adjusting the PCIe link speed in the BIOS when using a riser cable, particularly with PCIe 4.0 or 5.0 systems. Please check with your motherboard or riser manufacturer for the appropriate setting for your setup.

Recommended setup

We recommend connecting GPUs directly to the motherboard when using Redshift. 
We do not have a list of recommended riser cables.

We understand that fitting multiple GPUs alongside other expansion cards can be challenging. If your current layout requires risers, please contact your motherboard manufacturer or system builder. They can help you explore a suitable layout for your hardware and expansion needs.