Mode H period us V lines Sync
VGA TEXT 31.7777 449 -H+V I
EGA on VGA 31.7777 449 +H-V I
CGA on VGA 31.459 449 -H+V I
VGA Graphics 31.7777 525 -H-V N
Real EGA 45.764 365 +H-V I
Real CGA 63.695 262 +H+V N