VOGONS


First post, by sepp

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Dear Vogons,

in parallel to my other projects I'm currently trying to choose a graphics card for another retro project.
But: I find it very difficult to classify ISA cards.
I have a mainboard on which (according to the manufacturer's information) there is a Chips & Technologies CT W65545AE3 (written on the chip itself) card. According to the manufacturer, this should be a Vesa Local Bus connected card. It has 1MB of memory.
This is what the mainboard manual says:

Controller: VL-bus C&T 65545 VGA controller with Windows accelerator * Display memory: 1 MB on-board DRAM * Display resolution: […]
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Controller: VL-bus C&T 65545 VGA controller with Windows accelerator
* Display memory: 1 MB on-board DRAM
* Display resolution: Supports resolutions up to 1280 x 1024
* Non-interlaced CRT display up to 1024 x 768 with 256 colors
* Flat panel display up to 640 x 480 resolution
* Support True-color and Hi-color display capability
* Display output: DB-15 VGA connector, 22 x 2 pin header general purpose flat panel display connector

Target purpose of this system will be a DOS only machine. No Windows - only native DOS.

My questions would be:
Shall I stay with the onboard VGA card?
Or shall I add another ISA graphics card?
The only upgrade options are ISA cards - the system doesnt have a PCI Bus!
If I should go for another card: which one should I use when sticking to DOS only?

Reply 1 of 3, by megatron-uk

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If you only have ISA slots, then the on-board VLB VGA is going to be significantly faster; 8MHz 16bit transfers vs (at a minimum) 25MHz 32bit transfers. The only reason to consider an ISA card in that situation is if the onboard support is buggy or broken somehow and that the games you want to play don't work with it (hardware smooth scrolling broken, or doesn't support mode-x or something equally wacky). Bare in mind that DOS games use almost no acceleration features of video hardware - it's all about memory transfer speeds across the bus and framebuffer copy speeds.

If you do decide to go ISA, then the options for the fastest ISA cards are between those with the Tseng Labs ET4000 chip and the later models of the Cirrus Logic like the CL-GD5428 or 5429. Other options are not even worth considering.