What shutter speed is supposed to cause or contribute to the issue?
OM-D and 20 mm at 6400 ISO: only the noise that you would expect at this sensitivity. Quite usable results.
I own the OM-D and the Panasonic 20 mm. Great results - at 1600 ISO there is no problem at all.
The first Canon printer branded "Pro"? I own a Canon Pixma Pro 9000 Mark II.