The Open-Source NVIDIA/Nouveau vs. NVIDIA Linux Driver At The End Of 2019 - Poor But A Lot Of Hope
To no surprise given our Nouveau vs. NVIDIA benchmarks over the years, the open-source NVIDIA performance is very low... Kepler at least performs better thanks to its manual re-clocking support.
The GeForce GTX 600/700 Kepler series right now is the only NVIDIA generation close to really being usable with Nouveau, but even for some games the performance is still a wreck.