Yeah, it's both. We've improved the overall CPU performance a lot, while we decreased the GPU performance for higher accuracy. While common game systems still have enough GPU power to run the higher load at 4k, we think it's fine.
The next part is unrelated.
We also fixed a "bug" which just wasted lots of CPU power in the GPU thread while waiting for the CPU thread. This fix doesn't improve the performance (neither decrease it), but it reduces the power consumtion. Bad luck, in the task manager, dolphin now usually shows only half of the CPU utiliaztion.
So, now to your issue.
Dolphin runs a bit slower now because of your weak GPU performance. You think it's a bug not using all of the available CPU power (as the taskmanager shows it). But in fact, it's just a combination of both illustrated effects.
Theoretical problem.
We're most of the time emulating the CPU, sometimes the GPU. Both may run in parallel, but they very often don't. One emulation task can't (read: impossible) be split up to many threads. So please tweak your task manager to show your the CPU time of the dolphin process normalized to *one* core, not to all cores. This will be a bit more than 100%, so there are no more ressources to use.
The next part is unrelated.
We also fixed a "bug" which just wasted lots of CPU power in the GPU thread while waiting for the CPU thread. This fix doesn't improve the performance (neither decrease it), but it reduces the power consumtion. Bad luck, in the task manager, dolphin now usually shows only half of the CPU utiliaztion.
So, now to your issue.
Dolphin runs a bit slower now because of your weak GPU performance. You think it's a bug not using all of the available CPU power (as the taskmanager shows it). But in fact, it's just a combination of both illustrated effects.
Theoretical problem.
We're most of the time emulating the CPU, sometimes the GPU. Both may run in parallel, but they very often don't. One emulation task can't (read: impossible) be split up to many threads. So please tweak your task manager to show your the CPU time of the dolphin process normalized to *one* core, not to all cores. This will be a bit more than 100%, so there are no more ressources to use.