Large env maps...

I just wanted to confirm if there should be a direct correlation to an increase of render time depending on the size of the env map used for lighting/reflections/etc. I have done tests where I used a 1k map vs a 16k map, and on average, the 1k map is about 9% faster.

Does this seem about right?

yes, it does. Larger map means more cache misses when sampling it

Also don’t use the standard bitmap loader to load the HDRI. Use coronabitmap instead, I experienced almost 40% performance hit by using max bitmap loader