First, please read our guidelines for new help topics. In particular, note the backticks.
RHF can always be made faster than UHF. That said, I think more effort has been put into optimizing our RHF gradient code than our UHF gradient code. The slowdown you’re seeing probably is about Psi’s code rather than your input file.
If you want to know exactly what code, you’d need to look at the source yourself.