Increasing refl brightness of vraylight with sub-pixel on

[RE:FORM_STUDIOS]

I have some vraylights close to a glossy surface whose reflections I want to see blown out. With sub-pixel mapping off, the rendertime is way too high. With sub-pixel mapping on, it's as though the reflection is being clamped at 1 before being blurred by the glossy reflection.
My GI is BF/BF, no AA, DMC 1/100 0.08.
Is there anyway to use sub-pixel mapping without diminishing the brightness of glossy reflections?

[Morne]

how about using sub-pixel OFF and use clamp ON and set it to clamp at 2 or 3?
...or is your reflection just a small amount over 1?