Ubuntu 18.04 GZDoom Software Slowdown
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Please be as descriptive as possible in your posts (list your hardware and operating system, the version of the source port you are using, any mods you are running and how they're being loaded, etc.)
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Please be as descriptive as possible in your posts (list your hardware and operating system, the version of the source port you are using, any mods you are running and how they're being loaded, etc.)
This will help others to give you a solution!
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chowbar
- Posts: 19
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Ubuntu 18.04 GZDoom Software Slowdown
Hey guys, recently switched from Windows to Ubuntu 18.04 LTS and I’m getting sub 60 FPS performance in E1M1 with the software renderer. I’ve sudo apt updated and upgraded so I think my graphics drivers are up to date. When I had windows I never got less than 60 FPS in E1M1 in software mode.
Running Ubuntu 18.04 LTS with an Intel UHD 620 and an i3-8130U running GZDoom fullscreen 1080p while plugged in. Its not a screamer laptop but it never ran this poorly with windows. Is there anything I can do to prove performance? I presume Intel’s lazy and that they’ve been neglecting their open source drivers.
Running Ubuntu 18.04 LTS with an Intel UHD 620 and an i3-8130U running GZDoom fullscreen 1080p while plugged in. Its not a screamer laptop but it never ran this poorly with windows. Is there anything I can do to prove performance? I presume Intel’s lazy and that they’ve been neglecting their open source drivers.
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_mental_
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- Posts: 3820
- Joined: Sun Aug 07, 2011 4:32 am
Re: Ubuntu 18.04 GZDoom Software Slowdown
Are you sure that you are using exactly the same settings as on Windows?
There are two software renderers with two color depths each. Bunch of other settings may affect performance as well.
Did you install GZDoom from package or build it yourself?
There are two software renderers with two color depths each. Bunch of other settings may affect performance as well.
Did you install GZDoom from package or build it yourself?
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chowbar
- Posts: 19
- Joined: Sun Aug 19, 2018 10:28 pm
- Location: yay area
Re: Ubuntu 18.04 GZDoom Software Slowdown
Yup, Doom Software Renderer at 1920x1080 default software settings.
I installed the deb package and just loaded that.
Weird thing is that ZDoom 2.8.1 from the deb package runs totally fine. No FPS drops, 60 fps solid on E1M1. The software renderers can’t be that different right?
I installed the deb package and just loaded that.
Weird thing is that ZDoom 2.8.1 from the deb package runs totally fine. No FPS drops, 60 fps solid on E1M1. The software renderers can’t be that different right?
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Graf Zahl
- Lead GZDoom+Raze Developer

- Posts: 49252
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Re: Ubuntu 18.04 GZDoom Software Slowdown
They surely can. ZDoom 2.8.1's software renderer does not use any hardware acceleration on Linux, while modern GZDoom draws all 2D content using OpenGL.
It may be that your system uses software fallback for OpenGL and that is slow.
It may be that your system uses software fallback for OpenGL and that is slow.
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chowbar
- Posts: 19
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- Location: yay area
Re: Ubuntu 18.04 GZDoom Software Slowdown
Ah thanks for the explanation Graf. Anything I can do to improve performance or am I pretty much toast? Hardware accelerated rendering runs fine, but I do still like using GZDooms software mode for vanilla stuff. PrBoom doesn’t run super great on this system, and I don’t want to keep using ZDoom 2.8.1 as my main port.
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Graf Zahl
- Lead GZDoom+Raze Developer

- Posts: 49252
- Joined: Sat Jul 19, 2003 10:19 am
- Location: Germany
Re: Ubuntu 18.04 GZDoom Software Slowdown
First, post a GZDoom startup log. It may contain some useful info.
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chowbar
- Posts: 19
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Re: Ubuntu 18.04 GZDoom Software Slowdown
Yup here's the startup log
Hope this helps
Hope this helps
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Last edited by chowbar on Sun Aug 04, 2019 2:02 pm, edited 1 time in total.
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drfrag
- Vintage GZDoom Developer
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- Location: Spain
Re: Ubuntu 18.04 GZDoom Software Slowdown
Are you sure you were using the same version on windows? Try 'vid_rendermode 0' (8 bit).
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chowbar
- Posts: 19
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- Location: yay area
Re: Ubuntu 18.04 GZDoom Software Slowdown
Thanks for the suggestion, but I just confirmed that I was using 8 bit mode.drfrag wrote:Are you sure you were using the same version on windows? Try 'vid_rendermode 0' (8 bit).
Yeah I’m stumped, getting like 45-50 FPS on E1M1 which is puzzling the heck out of me.
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drfrag
- Vintage GZDoom Developer
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- Joined: Fri Apr 23, 2004 3:51 am
- Location: Spain
Re: Ubuntu 18.04 GZDoom Software Slowdown
I find surprising that the hardware renderer runs fine. Then try LZDoom, still has the pure software renderer.
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chowbar
- Posts: 19
- Joined: Sun Aug 19, 2018 10:28 pm
- Location: yay area
Re: Ubuntu 18.04 GZDoom Software Slowdown
Thanks for the suggesting LZDoom drfrag.drfrag wrote:I find surprising that the hardware renderer runs fine. Then try LZDoom, still has the pure software renderer.
I just loaded up E1M1 with LZDoom and it ran totally fine with the software renderer and hardware renderer.
Still totally stumped here guys, is there any software rendering options in GZDoom I should tweak? Any other suggestions?
Oh and FWIW, I just changed LZDoom to fullscreen at 1080p and I left the default software and hardware rendering options.