VOGONS


First post, by framebuffer

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Newbie

I'm doing some timedemo tests with Quake sw mode (Win98SE -> Restart in MS-DOS mode) and I just noticed that video cards have a big impact on performance.
This is something that I was not expecting, I thought that in software mode the video card was used just to display the output, so why I'm seeing differences between cards?

Could be something related to the DOS driver used by the video card?
Any idea?

https://framebuffer.io

Reply 1 of 2, by darry

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Rank l33t
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l33t

Some variables to consider :

- Video card internal bandwidth (EDIT: video RAM clock speed, type and bus width)
- PCI vs AGP bandwidth (AGP cards typically run at AGP 1x when initialized by BIOS, AFAICR, which is equivalent to 32-bit PCI at 66MHz , whereas PCI ones are 32-bit at 33MHz on most consumer boards . Someone will surely correct me if this is inaccurate)
- quality of VBE (VESA BIOS Extensions) implementation by a chipset OEM or in the TSR (OEM or third party) being used and whether an LFB is implemented (Linear Frame Buffer)
- Whether write-combing is enabled or not .

EDIT : See also PCI Video cards benchmark: Electric Boogaloo Edition