To start the case only has a depth of 317mm (12.87 Inches) which means I am
cramped for room. Vega 56 Nano (ITX) is 170mm (6.7 in) which is a huge
space saver compared to my current 270mm (10.6~ in.) GPU. If I go with a
Vega Nano or if they confirm a itx version for the 5700 or Radeon VII I
could afford to install one with room for a 120mm Radiator for liquid
cooling the system.
To answer he mATX question I never her of a GPU specified as mATX sizing,
On Itx ( for half size cases and some mATX) and full size GPU for
everything else to include majority of mATX cases.