VRAM
This page was last modified 15:07, 3 December 2018 by Mars2000you. Based on work by Rderooy and Grauw.

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 (not used on MSX). The V9990 can address up to 512kB video RAM.

Contents

Amount of VRAM by MSX Generation

Generation VDP Official Minimum Variations produced Recommended Minimum
MSX1 TMS9918A (*) 16kB 16kB 16kB
MSX2 V9938 (**) 64kB 64, 128, 256kB 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

MSX1 computers with MSX2 VDP

A few MSX1 machines have the MSX2 VDP (V9938). The MSX2 screen modes are normally not accessible, as they require more than 16kB VRAM.

MSX2 computers with MSX2+ VDP

A few MSX2 machines have the MSX2+ VDP (V9958). The MSX2+ screen modes are not accessible in MSX-BASIC.

MSX2 computers with just 64kB VRAM

MSX2 computers with just 64kB VRAM are rare, and for good reason. 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.

Machines with just 64kB VRAM were only offered in Japan and Argentina (schools only), and even Japanese publications like MSX Magazine advised customers to stay away from such systems.

These are the MSX2 systems with just 64kB VRAM:

MSX2 computers with 256kB VRAM

MSX2 computers with 256kB VRAM are very rare, only the NTT Captain Multi-Station comes with so much VRAM, probably because this computer has the V99C37-F Video Display Controller, that is able to display a palette of 256 colors selected amongst 260000 different colors.