when I am rendering an image of 6000 px x 4000 px with irradiancemap and detail enhancement on, what’s a good value of radius and subdivs? I get some problems (splotsches) in details when I use radius 120 and subdiv 0.5!
the irradiancemap settings are low at -6/-3.
i think the radius is too small for your resolution.
try a higher value, say double the value you have now.
if that does not help increase the suvdivs value step by step.
1.0 would be too much in sense of rendering-time.