Interesting results, in a nutshell it seems like Wayland/Xwayland performance on both nVidia and AMD wins slightly more than it loses. Once VRR is live in nVidia 545 series driver, for 3D games, Wayland is looking to deliver a great experience. Performance when Wine's Wayland code is ready to mainline will be very interesting given that Xwayland needs will be negated at that point.
(Apologizing in advanced since this seemed to turn spiral into more than I intended it to be)
I'm hoping to see Wayland + Nvidia get better over time. It has some promise, but at least on my system it still has plenty of issues. I'm on Arch (with KDE as my desktop environment) and I've just updated to the 535 driver, and some problems I've already run into while trying Wayland again:
Nvidia still hasn't provided GAMMA_LUT support, so no Night Light
KDE's Blur effects seem to break, for example - with Konsole, having the blur effect enabled and moving my cursor across the terminal causes the effect to tear, for lack of a better word. It seems to be a lower-level rendering issue because if I take a screenshot with Spectacle, you can't actually see the tearing
Discord normally (I say normally because I've just opened Discord right now to try to replicate it, and can't - it might be fixed, or it may just need time to reoccur again) has this odd issue where there's a huge latency when typing, so much to the point where characters start getting completely dropped, making what I can only describe as "alphabet soup" in the input field (even when trying the Discord AUR package that uses a newer version of Electron)
I've just tried to launch Steam (also under Flatpak) and it completely stalls at the "Logging you in" screen, however to be fair I hadn't launched it since Steam moved the new experience out of beta (and also enabled hardware rendering by default under Linux/macOS) so it could have the same issue when I log back into an X11 session... Launching Steam however has now caused the KDE system tray on my main display to stop rendering updates. Clicking on things still works, but there's no feedback (such as the hover affect, opening/closing windows do not cause their respective icons to show/disappear in the task switcher, the time is frozen, etc) - and only on one display.
And of course, due to the architecture of Wayland, I have no clue whether these issues are coming from either:
KWin's implementation of the Wayland protocol
A higher level KDE issue (such as in KDE Frameworks)
Nvidia's drivers
The applications themselves
XWayland for apps that don't natively use Wayland (Cinny and Discord both being Electron based apps tend to use XWayland, I don't know about Steam though)
An interaction with Flatpak and XWayland/KWin/said application
Or a combination of the above
(excluding the night light issue, which I know is 100% down to Nvidia not baking GAMMA_LUT support into their driver)
And that's quite unfortunate, because when I do step through all of the issues and launch say a game, or a high-res video, such as this 4k test video it is really smooth! Games feel incredibly great once its running. My assumptions are that a lot of this comes from Nvidia's bad drivers given that I don't tend to see people reporting these kinds of issues with Intel/AMD - but getting a new video card is just out of the question for me right now, and probably will be for a bit.
Since I can't even tell what part of the stack is causing these random issues, I don't even know who/what project to report these under.
About a month ago there was a spike in drama in regards to (from what I can understand) "Stop telling people to use X11 over Wayland, there are no issues with Wayland" and that made me a bit sad, because these issues (maybe barring the Steam one, which I'll fault myself for since I participated in the beta) straight up just don't occur on X11 - and I'm not saying X11 is perfect, but neither is (a) Wayland (session).
I had the same problem with Steam today, It was fixed by downloading the deb from Steams website. I am not running Wayland so I don't think this is a Wayland problem but could be wrong.
Yeah I meant to update my comment before I fell asleep, but I reinstalled the flatpak and it opened in X11 fine (I haven't been back in Wayland yet to test there)
For some reason, I can't get my Nvidia proprietary driver to work on Wayland. It automatically switches to software rendering whenever I enable Wayland. It works perfectly on Xorg.
Good to see both AMD and now Nvidia are performing well in Wayland. My experience has been that AMD loses nothing in performance on XWayland for the last few years and nice to see that confirmed.