50Hz- you got to make everything work at exactly that?

you need 50Hz outputs- in europe - everything needs to be 25/50

thats why we are testing 6 outputs at dvi 1080p50 from new mac pro- n541 build
all exact same refresh rate -

no datapath - all monitors exactly the same- you need active mini display port adaptors to dvi - unpowered - to do this

if you need 25/50 -
you should try this option

lots of monitors don't support EDID for 1080p50 - i have lots of monitors that don't - i have to replace them with ones that do
we had another recent thread about the correct EDID to do this-