I don't think this is correct. My understanding is that this is about more efficiently utilizing the GPUs available resources (e.g., cache) at the core-ish leve

I don't think this is correct. My understanding is that this is about more efficiently utilizing the GPUs available resources (e.g., cache) at the core-ish level. Like imagine if hyperthreads could share register space based on what they're doing at the time, I think.