Well, I've done some further testing.
I have completely uninstalled Lucid VirtuMVP.
With the monitor connected to the nvidia discrete card, I have not available Quick Sync in GOM Video Converter. In GOM VC I can only choose "Intel H264" in codecs tab (item relating to Quick Sync is not available). Intel Quick Sync encoder doesn´t work in MediaCoder.
With the monitor connected to the integrated graphics I have available Intel Quick Sync encoder in MediaCoder and GOM Video Converter (and works in both)
Regarding the GOM VC encoding: Using "intel H.264" or "Intel Quck Sync" I have not found differences in speed with my i7-3770. Perhaps in other lower frequency processors Quick Sync have advantages over "intel H.264".
Regarding Lucid Logix: It's all very confusing and I do not understand what this role does about Quick Sync. Maybe with Lucid you can use Quick Sync when the monitor is connected to the discrete graphics card, but only in the applications supported by Lucid. I do not know.