This is a Zeos branded card based on an uncommon NCR 77C22E+ chipset. This is likely a 32bit GUI design with a 16bit host bus interface. A solution that is not dissimilar to Cirrus Logic GD542x VLB cards.

The card likely only appeared in Zeos line of 486 PCs at the early days of the VESA local bus in early 1992 or 1993. The OEM nature of the card is highlighted by the absence of standard stuff like normal socketed VGA bios or a feature connector.

DOS performance is relatively good. However, performance in Windows acceleration is rather poor for a VLB card. In some benchmarks, it is lagging even behind ISA cards. The card is not supported by UniVBE, but some extra VESA and text modes can be enabled by loading a driver in CONFIG.SYS.

Surprisingly, Windows 3.1 drivers I’ve found, offer no 16/24bit modes so the maximum the card can do is 256 colours. Not sure if this is a limitation of drivers or the chipset, although the Bt475 80 MHz RAMDAC should in theory support direct/true colour modes.

3 comments on “Zeos NCR77C22E+ VLB card

  • Mike

    I have one of these and even in DOS it seems limited to 256 colors. Is yours able to display more than 256 colors at a time? When I run Doom, it looks like it’s in CGA mode or something.

    • mpe

      It is actually reduced to 256 colours even in Windows. I believe the RAMDAC does not support high-colour. It is the only vlb card I know about without high/true colour support.

  • Samir

    We ran into this issue on one of the cards we got back in the day instead of the Diamond high-color. While the card had great specs and the right RAMDAC for high-color, the drivers just didn’t support it. We eventually moved to an ATI card and put the other card in a 486DX system we made from the parts of upgrading our main 486. Good times.

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