GvM

thanks again stevenong.
But in my case only switching of matra's settings help here.
Either changing brightness in drivers/houdini or setting compatibility mode in mplay doesn't help.
Also houdini writes “UT_NetPacket::write: No error” to its console sometimes, when I render the scene after some changes in mplay's settings.
Though it works pretty well now.

omg! now it renders garbage with default render settings (picture 1, note 16 bit float by default)
but switching Quantization in mantra settings to 32 bit float, 16 bit integer, 8 bit integer fixes this… (picture 2)

Installation of catalyst 8.5 fixed the bug in network pane.
Still moving of objects delayed when using grid snapping.
PS won't roll back to older drivers because of some required improvements in new.