VRAM
This page was last modified 13:38, 2 November 2021 by Mars2000you. Based on work by Gdx and Grauw and others.

VRAM or Video RAM is a type of memory that is dedicated to the video display processor (VDP). All MSX computers have dedicated VRAM, unlike most other 8bit computers of the era which shared the main RAM with the video processor.

The TMS9918 can address 16kB video RAM. The V9938 and V9958 can address up to 128kB video RAM, as well as an optional additional 64kB which can’t be displayed directly (very rarely used on MSX). The V9990 can address up to 512kB video RAM.

Amount of VRAM by MSX Generation

Generation VDP Official Minimum Variations produced Recommended Minimum
MSX1 TMS9918A (*) 16kB 16kB 16kB
MSX2 V9938 (**) 64kB 64kB / 128kB 128kB
MSX2+ V9958 128kB 128kB 128kB
MSX Turbo R V9958 128kB 128kB 128kB

(*) MSX2 VDP (V9938) on a few MSX1 machines
(**) MSX2+ VDP (V9958) on a few MSX2 machines

MSX2 computers with just 64kB VRAM

MSX2 computers with just 64kB VRAM are rare, and for good reason. They were only offered

Even Japanese publications like MSX Magazine advised customers to stay away from such systems.

They cannot use some of the video modes of the V9938 VDP, and for the video modes that they can support, they are able to hold fewer screens in memory. As such the amount of MSX2 software that runs on such a system is greatly reduced.

You can see a list of MSX2 software able to run with just 64kB VRAM on Generation-MSX.

MSX2 computers with 256kB VRAM

Only the NTT Captain Multi-Station comes with 256kB VRAM, because its V9938 is enhanced with the V99C37-F Video Display Co-Processor.

This co-processor is able to display a palette of 256 colors selected amongst 260000 different colors (probably in screen 8 or an extra screen mode).