Got my A4000, had all the networking goodies preloaded, working fine on SVGA
I have no idea what mode I'm in, it's definitely 640x480 but not sure if 16 or 256 colour.
For Risc OS 2 & 3.x. Navigate your mouse pointer down to the palette icon, left one of the two on the right of the icon bar, click middle button on the mouse. Mouse over the tear off on 'Mode' item in the menu, the 'most suitable' mode numbers for your monitor are listed, included information is the number of colours available to you in each mode. There is a tick beside the one that your desktop is currently using. It is then a case of looking up this number in the manual, or internet to confirm the X,Y resolutions.
Not entirely sure if Risc OS 4 was supported in these machines, so I won't describe what you will find here with anything newer than 3!