Emulator

The Wii menu is not the only title that happens. I also tried Wii Play. Here at 5.0-5833 I have 60 FPS all the time, at 5.0-5874 and later only at the very beginning.
I also noticed that disabling the antialiasing feature significantly improves performance, which is rather surprising given my graphics card, isn't it? Also, I've found that if I use the free camera (provided by Dolphin) and swivel it in a direction where there are no objects to render, the performance also improves.
I have also tried two drivers for my graphics card. The newest and the second newest. Both did not solve the problem.
Do you have any suggestions as to what else I could try? It seems like the problem is not reproducible for you. :(

No, it is. We know. It's marked questionable simply because you bisected to Hybrid XFB. Which is an entirely known performance hit. We knew that when we merged it.

If it were me I would have just marked it as working as intended but questionable is still valid in the sense that performance improvements could be made down the road.

But. In any case, no this isn't a bug or regression in the sense that you're thinking.

Sometimes certain things get slower so things can get better.

Would not it be possible to have both as an option? So the choice between "No XFB", "Virtual XFB" and "real XFB" and the option "Hybrid XFB"? Because there are many games that do not make any use of the XFB and for them, the absence of the old options alone is a deterioration. Please clarify me if I'm wrong. :)

It's not possible to keep all the options as they use a completely different method of emulating the XFB. The old XFB options were less maintainable (the new XFB options reuse a lot of our EFB code,) and are easier to use. More games work without costly, slow features like readback. If you have to turn down your AA slightly for Dolphin to maintain higher compatibility, that's a sacrifice we're willing to make...

That said, there isn't a reason that MSAA should be significantly slower with HybridXFB.

Okay, then I just use the version before hybrid XFB as long as I do not have a new processor. Because I want to disable neither the anti-aliasing nor reduce the resolution.