The physical display isa CGA compatible display. There are 3 text modes: 80 characters by 25 lines, 64x18, and 40x16. The 64x18 and 40x16 text modes are windows onto a CGA standard 80-character by 25-line display RAM. The hardware/BIOS provides for windowing the physical display around the larger display; the software underneath is not aware that it is displayed on a smaller subset of the 80x25 screen.
The graphics modes available are 640x200 (black and white), 320x200 (4 shades of gray), both of which are CGA compatible, and a nonstandard graphics mode which is 240 columns by 128 rows is also included (this is for 95LX compatibility). The 95 compatibility graphics mode is shown as a small window centered on the 320x200 display.