Wow, Einstein, now!
Seriously, Warangel, I think you overdid your settings, a+2 radiosity quality boost? Are you out of your mind, my friend! lol!
This quality boost setting is only here because sometimes, artifacts can appear on radiosity renders (noise, mostly), and it's inheritent of this lighting model in any renderer. But in 99% of the time, a -1 setting is good enough, and will not create noise.
And though radiosity is a lot faster in Vue6, I don't see its advantages against GR or AO for outdoor renders, most of the time.