Comment by Findecanor

Later Amigas also supported VGA monitors with 31kHz horizontal refresh rate, with just a passive adaptor. I used a VGA monitor with my Amiga 1200 up until I switched to PC, and a tweaked video mode with 704×520 pixels.

If you wanted to play games on an Amiga or an Atari ST you needed to use a TV-signal compatible 15kHz monitor or a Multisync monitor. I ran desktop programs in 640×200 mode with four colours on both my ST and my Amiga 500 before I upgraded.

There were also "flicker fixer" add-ons for the Amiga, converting the interlaced modes to VGA signals: one was built into the Amiga 3000.