visual studio xaml editor lag

Question

I am experiencing a huge amount of lag while using Visual Studio (2019, 2022) xaml editor. So much lag that the editor is frustratingly unusable. Visual studio itself is not slow, so none of the "improve performance" articles that I can find are relevant as general performance is good. This problem really only manifests in the xaml editor.

I believe this might be related to how the Motherboard/CPU is configured (perhaps to use energy saving features so as to consume less energy). However I have no evidence to really prove this, just a gut feel as when using the xaml editor, I hear the CPU fan spin up and I can see activity on task manager showing 6 cores in use, and clock speed increases from its base of 4Ghz to around 4.35Ghz.

I also conclude this because I only experience this problem on one machine, which is a new build with an AMD Ryzen 9 5900X 12 Core cpu. The older machine that works fine has an intel i5-6600K 4 core CPU running at 3.5Ghz. When editing on the old machine, the experience is normal and fine, but with the AMD cpu machine, the visual studio xaml editor is just unusable.

Even a simple action such as just trying to select a few lines of xaml (shift + up cursor to select a few lines), produces lag, and I can hear the fan spin faster, see the CPU speed rise, and if I keep doing it, the cursor is jumping around all over the place and I end up typing in the wrong place, etc, etc.

The new machine has a completely clean/fresh windows build with developer tools. Both bios configurations are reasonably vanilla, despite both CPUs being the unlocked versions, I don't (well not in this circumstance) use any form of overclocking. Also, Visual studio installations are pretty standard, with no customisations.

I have been through the bios (ASUS ROG STRIX B550-F motherboard) and there is nothing obvious that I can see would be causing this - all the settings are on their defaults. I also tried the xaml options within visual studio, but they made no difference and I need to use the XAML designer so disabling it is not an option.

However I assume there are either features in the bios that I could alter? Or perhaps there are other software options in visual studio that might change this behaviour?

Any thoughts or suggestions on what to look at much appreciated.