Comment by spookie

I chose to focus on the fact the frag stage is already tracking those changes because at that point it's basically free. And you don't need to worry too much.

To answer your question, which is very pertinent, they seem to use different hardware accelerated mechanisms. In the compute stage, wave based derivatives are used, and you need to account for different lane counts between GPU architectures.

Understanding that now makes me believe you're right. But one needs to benchmark them to be sure.