photoshop incredibly slow and laggy with shape tool

using the shape tool, no matter how simple is so slow, whereas the rest of the program is fine. Just clicking on a shape takes a couple seconds of nothing before it is selected, and even worse if you want to create, edit one (changing colour, stroke etc, all super slow).

As you can see, selecting a rectangle takes seconds to complete, whereas a smart object is instantanious.

Any ideas what might be causing this, and how to fix it? An older version of PS (CS6 iirc) was the same on this machine, never got to the bottom of it but its becoming intolerable.

Current version should be up to date, same with drivers etc.

Running a AMD Ryzen 7 2700 8 core CPU and nvidia RTX 2070 GPU.

I remember a LONG time ago this issue was never present on much worse hardware.