Is it possible to get 1.21 with Cuda 11.5 for Linux?
Not yet.
Also if I have a high CPU load should I use the no cpu usage switch?
Doesn't work for AMD
Does dual mining eth zil on the same pool need any tags or slow things down like ssl?
AMD cards doesn't have a dag cache implemented yet, so the dag creation on switch will slow down.
NVIDIA cards with more than 6GB memory will cache the dag and the switch is smooth.