When playing around with the crane arm from the exercise in the Fundamentals of Rigging course, I noticed that the viewport animation playback speed reached 42-48 fps when I had set the frame rate to 30 fps in the properties. The only way to get it to stay around 30 fps was by viewing my animation in rendered mode. I was using Blender 2.83 to stay consistent with the course.
And then when doing the Arcing Ball Bounce exercise from the Animation Bootcamp course I barely got 20 fps unless turning on "simplify". Even with simplify turned on and viewing in solid mode it only reached 20-22 fps. Using Blender 3.3.
Anyone experienced issues like this before? It can get annoying when I'm animating and not paying attention, because the final render will be totally different speed. I'm not saying it should stay at exactly 24fps or 30fps at viewport playback, but that I'm experiencing huge inconsistencies. That a simple sphere can barely reach 24fps but a much more heavy scene goes up to 48fps, totally ignoring my settings.
I bought a used 3090 graphics card a few months ago from an online store that deals with used cards. I have stress tested and benchmarked it and everything seems fine. It's just this one issue I have experienced. I normally wouldn't buy used but there is no way I can afford a new one. A blender bug? Driver/Card issues? Perhaps difficult to tell but still wanting to ask just in case someone knows...
As you say, there is no way the ball can have frame rate issues, it's too simple, for sure that sounds like Blender bugs, drivers problems and that sort of things. I guess the only thing is wait for Blender bug fixed version and new drivers. Have you tried it in another computer? Maybe it's even a Windows thing? But that's why I always use a play blast when I want to really judge how my animation is going. I don't trust the viewport even when it says it's going at 6ofps.
Hi Markus,
That's really weird!
I cannot reproduce this in 2.83 (or other versions I tried); the set Frame Rate is never exceded in the Viewport in my tests:
That's not just a bug, that's an 'Überbug'...ordering 6 chickenwings and getting 6 whole chicken...
My first guess would be a driver issue, but that usually makes things worse, not 'better'...🤔
Let me sleep on this...
...and while I sleep, maybe @waylow the Wise knows...
Thanks guys for taking the time to reply. And thanks spikeyxxx for trying to replicate it. Although, I made a typo. Should be Blender 2.93, not 2.83...I tested both animations again in the viewport and the crane arm has slowed down a little. The highest I can go now is 40 fps when setting the frame rate to 30fps. (but the highest is 60 fps if I change frame rate in properties.)
I also tested the arcing bouncy ball. The highest I can see in solid mode is 22fps, even when I manually set frame rate to e.g. 60fps. That ball really stomps my graphics card it seems.
I also tried both animations on my old computer with a GTX 1080. The ball got 17-18fps as the highest. The crane got 31-34 fps which is a lot more reasonable. But then again, a much weaker card.
Windows installed an update yesterday and perhaps that's why the crane won't go as high as before. So maybe it's a combination of windows, blender and driver/card issue. Or even... it's always been this way and I never noticed it since I was using a rather old card, by today's standards.
Ah, the dreaded nuclear option! Not sure about moving to a peaceful land kind of feeling though. The system is fairly new, and I mostly just use it for 3D and related things. Anything else I do on my old computer. And also there is no guarantee that reinstalling windows will actually fix the issue. I knew asking this question was a long shot, but for now I can still live with it. Just have to be more careful during animation. I'll definitely keep your suggestion in mind 
dostovel , just in case it gets worse for some reason.