It is getting hard, unless I mistaken what was suggested by nvidia .
Thus, following what was suggested by nvidia as a no-barrier solution,
https://devtalk.nvidia.com/default/topic/545186/enabling-pcie-3-0-with-nvreg_enablepciegen3-on-titan/?offset=10#4021328
I updated the kernel boot string by
1) typing 'e' at grub prompt,
2) adding the option to the linux line,
3) Ctrl-x to boot
If that procedure is correct (probably it is, as
francesco@gig64:~$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-3.10-3-amd64 root=/dev/mapper/vg1-root ro 1.
nvidia.NVreg_EnablePCIeGen3=1 quiet
francesco@gig64:~$ )
then, no luck. Both LnkCap and LnkSta were at at 5GT/s, as for PCIe 2.0.
Molecular dynamics, accordingly, was not accelerated.
I wonder whether "1." preceding "nvidia..." is what is needed for a grub
bootloader option. I did not find any other instance about that nvidia
suggestion on internet.