I'm honestly not sure why the Ray Detail Multiplier isn't set to 1 by default, and let people adjust as needed. For the freeware version, without this set to 1, you get black tears in most your renders, sand, water, seams of planes, lateral, normal, etc.
Even when you render at MPD .6 AA 0.6 with cache sliders at, or above max.
And considering I'm on "comparatively low-end hardware" there is really no impact beyond maybe a minute or two in render time (if that). So. Yeah...