Nouveau supports pstates for some cards, you can reclock them and get better performance, 80% ~ of the Nvidia blobs in my case. As it says here (https://nouveau.freedesktop.org/), reclocking is supported on GM10x Maxwell, Kepler and Tesla G94-GT218 GPUs. I have tested it on Fedora 33 with a MSI GT 710 2GB, no problems so far.

For listing the available pstates of the 0 card, run:

sudo cat /sys/kernel/debug/dri/0/pstate

You will get something like this:

07: core 405 MHz memory 810 MHz
0f: core 653-954 MHz memory 1600 MHz
AC: core 953 MHz memory 1600 MHz

In my case we have the powersaving option (0x07) and the performance one (0x0f). The last one, AC, is a buggy option, ignore it. What we are interested in our case is the performance pstate.

To test if it works before enabling it permanently, do

echo 0f | sudo tee -a /sys/kernel/debug/dri/0/pstate

If you find that setting stable, lets move to the next step.

Add this kernel parameter in your GRUB config. The number must be the decimal of the number you got earlier (0xf=15)

nouveau.config=NvClkMode=15

Remake grub.cfg and you should be good to go!