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First post, by brassicGamer

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Hi folks, firstly I wanted to give some love for the forum redesign - it's working brilliantly on every platform I've tried it on, and has made it even easier for me to connect with the buzzing community here.

Secondly, I almost exclusively use DOSBox to play Indianapolis 500 on my Mac laptop. It's been flawless for ages, but since updating to Catalina (and to 0.74-3) games (the aformentioned Indy 500 and Pinball Fantasies) are now suffering from stuttering every second or so that makes games unplayable. I don't know if you've heard anything similar from elsewhere but here's what I've noticed so far:

a) no amount of configuration file changes seem to make a difference
b) it was fine before the update
c) the games work fine in a DOS VirtualBox VM
d) the games work fine in DOSBox 0.74-3 within a Windows 10 VirtualBox VM

Sorry it's not more informative at this stage and if it's just me being a goose.

Check out my blog and YouTube channel for thoughts, articles, system profiles, and tips.

Reply 2 of 13, by almeath

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jmarsh wrote on 2020-02-25, 00:53:

When you upgraded to Catalina you lost the ability to run 32-bit apps, and the 64-bit version of DOSBox 0.74-3 is significantly slower than the 32-bit version.

Have you tried the 64-bit SDL2 daily snapshot build by Dominus? I use this on my i9 iMac and I can get 200+ FPS on the Quake benchmark and 1500+ on Chris 3D benchmark when forcing dynamic core and max cycles.

DOSBox SVN for macOS (x86-64) - customized with Munt MT-32, Nuked OPL3, 3dfx Voodoo, Extra RAM, Large HD, and more.
https://github.com/almeath/DOSBox-SVN-64-bit-for-macOS

Reply 3 of 13, by Dominus

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Yes, try the SDL2 or even the normal snapshot and make sure you have opengl or metal (with the SDL2) as output. Surface is seriously slow.
Jmarsh made the 64bit dynamic core much faster in SVN, so both should give a nice boost

Windows 3.1x guide for DOSBox
60 seconds guide to DOSBox
DOSBox SVN snapshot for macOS (10.4-11.x ppc/intel 32/64bit) notarized for gatekeeper

Reply 4 of 13, by brassicGamer

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Dominus wrote on 2020-02-25, 08:02:

Yes, try the SDL2 or even the normal snapshot and make sure you have opengl or metal (with the SDL2) as output. Surface is seriously slow.
Jmarsh made the 64bit dynamic core much faster in SVN, so both should give a nice boost

Oddness. Downloaded SDL2 and found no difference. Systematically tried the different combinations of output and renderer and found that using surface fixed it. Went back to the non SDL2 version and found the same result. Huh.

Check out my blog and YouTube channel for thoughts, articles, system profiles, and tips.

Reply 5 of 13, by Dominus

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that's really odd.

Windows 3.1x guide for DOSBox
60 seconds guide to DOSBox
DOSBox SVN snapshot for macOS (10.4-11.x ppc/intel 32/64bit) notarized for gatekeeper

Reply 6 of 13, by almeath

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Dominus wrote on 2020-02-25, 16:40:

that's really odd.

Maybe vsync is enabled? That one setting has a drastic impact in the benchmarks I have run, for example it reduced the Quake FPS from 220 down to 40 (SDL2 build) I get the same result with metal and opengl.

It can also cause sound problems (stuttering and/or slowdown) but it’s not consistent. In some undemanding games it works well and prevents jerky scrolling and screen tearing without a noticeable performance impact.

DOSBox SVN for macOS (x86-64) - customized with Munt MT-32, Nuked OPL3, 3dfx Voodoo, Extra RAM, Large HD, and more.
https://github.com/almeath/DOSBox-SVN-64-bit-for-macOS

Reply 7 of 13, by jmarsh

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almeath wrote on 2020-02-26, 01:56:

Maybe vsync is enabled?

I was going to suggest the same. It seems common for non-windows systems to enable vsync even though DOSBox tells OpenGL not to use it, which causes slowdowns if a game tries to render faster than the current refresh rate (e.g. a 70fps game running on a 60fps display). Easy to diagnose by checking if the problem goes away with frameskip set to 1.

(Some people seem to have a misconception that vsync is required to prevent screen tearing; it's not, that's what double-buffering is for.)

Reply 8 of 13, by brassicGamer

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vsync wasn't enabled, frameskip=1 had a positive difference, frameskip=2 eliminated it.

edit: for the hell of it I enabled vsync. Also fixed the problem, with frameskip=0. Go figure.

Check out my blog and YouTube channel for thoughts, articles, system profiles, and tips.

Reply 9 of 13, by almeath

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In the SVN SDL2 build is there only an on/off for vsync with the vsync=true/false setting?

Are there any granular settings that can be used like in earlier DOSBox versions?

(I did search around, but there is not much to go on)

DOSBox SVN for macOS (x86-64) - customized with Munt MT-32, Nuked OPL3, 3dfx Voodoo, Extra RAM, Large HD, and more.
https://github.com/almeath/DOSBox-SVN-64-bit-for-macOS

Reply 10 of 13, by almeath

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I only ask because the SDL2 SVN build seems to be the first build where enabling vysync actually has an effect in macOS. It works great in some games (i.e Epic Pinball, Lemmings Chronicles) but horribly in others (i.e Lemmings 2, Warcraft 2) where it causes major slow downs and sound problems.

As it can severely impact performance, I would like to be able to test different refresh rates etc. , but it seems it’s not possible in SDL2. Enable/disable seems to be it.

DOSBox SVN for macOS (x86-64) - customized with Munt MT-32, Nuked OPL3, 3dfx Voodoo, Extra RAM, Large HD, and more.
https://github.com/almeath/DOSBox-SVN-64-bit-for-macOS

Reply 11 of 13, by brassicGamer

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almeath wrote on 2020-03-13, 02:54:

I only ask because the SDL2 SVN build seems to be the first build where enabling vysync actually has an effect in macOS. It works great in some games (i.e Epic Pinball, Lemmings Chronicles) but horribly in others (i.e Lemmings 2, Warcraft 2) where it causes major slow downs and sound problems.

As it can severely impact performance, I would like to be able to test different refresh rates etc. , but it seems it’s not possible in SDL2. Enable/disable seems to be it.

Thanks for the suggestions, I'll give them a go once I've competed Tie Fighter (which is mostly behaving).

Check out my blog and YouTube channel for thoughts, articles, system profiles, and tips.

Reply 13 of 13, by almeath

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engdahl80 wrote on 2020-03-29, 15:16:

Hi, I have searched for the 64-bit SDL2 build by Dominus that you mention. I have stuttering issues as well in Catalina. Could anyone link to it?
Thank you.

Can you PM me about this?

The link to the SDL2 build was taken down:

Source code for Dominus's DOSBox SDL2 macOS 64-bit

DOSBox SVN for macOS (x86-64) - customized with Munt MT-32, Nuked OPL3, 3dfx Voodoo, Extra RAM, Large HD, and more.
https://github.com/almeath/DOSBox-SVN-64-bit-for-macOS