Shponglefan wrote on 2023-03-19, 02:36:
Commander Keen 4 overworld is easy to use for testing for judder. @ 70Hz, you should get smooth scrolling on the overworld. If only 60 Hz, the judder is obvious.
Commander Keen is not actually panning the map or game screens at 70hz natively, but only at 35 hz. However, even then, the scroll in the game is not hard-locked perfectly on 35hz, but will occassionally miss frames.
Games off the top of my head that come to mind that do have smooth panning motion:
- Lemmings game main menu, there is a 70hz scrolling text screen,
- One Must Fall, although there are no specific 70hz visible panning elements, but you'll have to play the game to "feel" it.
- Pinball games in their table intro view, where the game pans across the pinball table when gameplay is not yet activated. (these do use different video modes with different refresh rates, so set them to lowest 320x200 to get a 70hz mode)
- The demo "Yo!" from Future Crew does smooth panning at 1px per frame, although now actually I can't recall 100% if that demo was 70hz, or if it actually was 60hz, I'd have to check. Though this is still good for smooth scroll testing.
I have been validating monitors and graphics cards in my test lab for DOS use. Here are parts of my test suite, all of this stuff is of course subject to your own interest levels and what you care about:
- the common DOS video modes are:
- 320x400 (VGA mode 13h),
- 360x400 (CGA 00h/01h 40x25 text mode emulated on VGA),
- 640x400 (CGA 06h/EGA 0Eh mode 640x200 mode emulated on VGA),
- 720x400 (CGA 02h/03h 80x25 text mode emulated on VGA), and
- 640x480 (VGA mode 12h).
How well does it work in these?
- does the monitor allow a "force 4:3" mode on all of the above input modes? Or do some of them remain 16:10 or 1:1 aspect?
- does the monitor work with nonstandard game video modes on pinball games such as Pinball Fantasies, Pinball Illusions, Psycho Pinball, etc.?
- are the pinball games actually playable, or is video lag too much that hitting the ball in pinball games feels "off"?
- does the monitor work with nonstandard game video modes on non-pinball games such as Jazz Jackrabbit, Earthworm Jim, The Incredible Machine 1 and 2, Cyril Cyberpunk, etc.?
- does the monitor work with VGA Mode-X modes: Quake, Scorched Earth, Lost Vikings, etc.?
- does the monitor work with glitched video modes with negative horizontal or vertical sync porches, such as Jump & Bump (and the Pinball games)?
A good roundup of games with the above video modes can be found at http://nerdlypleasures.blogspot.com/2014/09/o … tions-when.html
- does the monitor quickly sync on changes in video mode? e.g. Lemmings and Jazz Jackrabbit change video modes during ingame transitions
- like already mentioned, does the setup work with different refresh rates: 50hz, 60hz and 70hz, not just to display an image, but to do so without frameskip?
- if SVGA/VESA/multisync modes are of interest:
- what are the max pixel clock, horiz. scanline rate and refresh rates the monitor supports? (from display specifications)
- does the SVGA 800x600@56hz video mode work? UniVBE's UniCenter tool allows testing these.
- do the SVGA 1024x768@86hz interlaced (43hz progressive) and 1280x1024@86hz interlaced (43hz progressive) video mode work? (last I recall trying with OSSC, I think OSSC itself did not support these, although it did support 800x600 interlaced, which is super rare to even exist on DOS graphics cards) Windows 3.1 with proper SVGA drivers allows testing this.
- do the VESA higher refresh rate modes work? E.g. 640x480@70,72,75hz? Or 800x600@60,70,72,75hz? UniVBE's UniCenter tool allows testing these.
- does the monitor work with SVGA text modes e.g. in Word Perfect? These are text modes like 80x(30-60) lines, 100x(25-60) and 132x(25-60) columns.
- if there is an audio external line-in 3.5mm jack, does it actually work while viewing display from HDMI input, and what is the audio quality of the built-in speakers like? (on Asus ProArt e.g. 3.5mm input does not work properly if HDMI input is active)
- does the setup work with exotic demo scene effects? LCD monitor VGA compatibility database allows testing these.
- how good is the panel picture quality? If it is e.g. an older panel, does it have ghosting in, say, Prince of Persia, where there is a white character running around against a black background, a good test for sharp contrasted animation.
- is the OSD menu and buttons comfortable to use? ("do I love this ergonomically paired with my retro PC")
You specifically mention Dell. I find that I have quirk notes marked down about the following Dell monitors:
- Dell 2007WFP 1680x1050:
- occassionally when the input resolution changes, there are random glitching scanline artifacts that appear on screen. These disappear if one goes in the picture aspect ratio settings, and switches aspect between Full <-> Aspect, and back. (for example, toggle the setting Aspect->Full->Aspect)
- 70hz video modes do sync, but do frameskip, and is not vsync-locked but exhibits visual tearing artifacts
- is unable to display 720x400 input video mode in 4:3 forced mode
- Dell 2007FPB 1600x1200:
- 70hz video modes do sync, but do frameskip, and is not vsync-locked but exhibits visual tearing artifacts