Reflection render speed: bug or feature?

[Leftover]

I noticed render time of surfaces with blurred reflection applied depends on reflection level dramatically. Test scene is a box with reflective walls and rendered in Raytace mode. For reflection level 10% - render time is 4 sec, for ref. level 50% - render time is 28 seconds, which is 7 times longer. So there's a question is it bug or "feature" (a way optimization algorithm works)?

It affects only surfaces which have "Ref. Blur" > 0.
It works same way in OB7 and OB8.

I have a scene with big metalic surfaces and render time is too high. Actually i would be satified if slight and fast reflection would be brighter (without all extra details that show up with higher reflection values).
Is there some workarounds for such situation? maybe reduce recursion limit for selective surface, or multiply reflection buffer somehow?

[mk]

yes you right. I have noticed too.
But you can reduce the render time by changing the 'Blur treshold' in the Kray panel (Quality tab).
I start with 0,1 and go down until I get what I want (quality vs time).

mk