NVreg_EnablePCIeGen3=1 for Maxwell GPUs

I have an older system with a 3930K processor. I have been using the modprobe option NVreg_EnablePCIeGen3=1 to allow for my NVIDIA cards to run at 8.0 GT/s. With my previous 680 and 780 Ti cards, the link speed would negotiate at 8.0 GT/s and the CUDA apps I ran were stable with this option.

Recently, I switched to 980 Ti cards. The module option no longer seems to have any effect as the cards run at 5.0 GT/s. All other hardware and software configuration is identical with exception of the change in graphics cards.

Would it be possible to have this option supported with Maxwell GPUs with the next driver release? I am currently running Linux driver 355.11 and Slackware64-current. Thanks.

Sorry for resurrecting this old thread, but I had been looking for a solution myself and stumbled upon many unanswered questions like this one.

On Ubuntu, you need to also run update-initramfs (or the equivalent for your distro). More details here: https://ubuntuforums.org/showthread.php?t=2325412&p=13613166#post13613166