Does anyone know why my RDR increases when I cap my framerates?

I am using a Pimax Crystal light and using the limit frame rate to 1/2 frame rate in the Pimax app (90 Hz - so its limited to 45).

Without capping the frame rate, I have 13ms RDR.

Capping I get 21ms RDR.

I know just the basics and I am hoping someone with much more knowledge of these things can help me out.

Thanks

Because you cap at 45FPS which translates to 22.2ms for every frame? I guess the RDR then simply replicates this fixed rate. Without cap and 13ms RDR, my guess would be that your FPS are also around 75FPS, correct?

Thanks so much AnkH, that makes sense.

Without the cap my FPS is around 58, I must be losing something elsewhere.

Thanks again