GPU B renders much, much slower than GPU A

Lubuntu Support
1

Kind of strange behavior exhibited from my new Lubuntu install. I have two video cards installed on my system and one renders much slower than the other.

Video card A is a RS880 [Radeon HD 4250] which is onboard and video card B is a RV730 XT [Radeon HD 4670] which is an addon PCI express card.

Video card B has less than stellar performance and it is especially noticeable using OpenGL.

Some details:
From lshw:
*-display
description: VGA compatible controller
product: RS880 [Radeon HD 4250]
vendor: Advanced Micro Devices, Inc. [AMD/ATI]
physical id: 5
bus info: pci@0000:01:05.0
version: 00
width: 32 bits
clock: 33MHz
capabilities: pm msi vga_controller bus_master cap_list
configuration: driver=radeon latency=0
resources: irq:18 memory:c0000000-cfffffff ioport:d000(size=256) memory:feaf0000-feafffff memory:fe900000-fe9fffff
*-display
description: VGA compatible controller
product: RV730 XT [Radeon HD 4670]
vendor: Advanced Micro Devices, Inc. [AMD/ATI]
physical id: 0
bus info: pci@0000:02:00.0
version: 00
width: 64 bits
clock: 33MHz
capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
configuration: driver=radeon latency=0
resources: irq:25 memory:d0000000-dfffffff memory:febf0000-febfffff ioport:e000(size=256) memory:c0000-dffff

From uname -a:
Linux dinoPC 5.5.0-7.1-liquorix-amd64 #1 ZEN SMP PREEMPT liquorix 5.5-10ubuntu1~eoan (2020-03-01) x86_64 x86_64 x86_64 GNU/Linux

From glxinfo | grep ā€œOpenGL versionā€:
OpenGL version string: 3.0 Mesa 19.2.8

Iā€™ve been driving at this problem for sometime now to no avail. Help would be very appreciated!

2

You havenā€™t mentioned your release of Lubuntu, but if itā€™s a new install your kernel doesnā€™t match any supported release of Lubuntu so it could be youā€™re running something that isnā€™t Lubuntu.

I would check what youā€™re running, or provide details on what youā€™ve done as details provided do not match a new Lubuntu install.

3

Iā€™m sure I wonā€™t have anything to offer. But, Iā€™m curious. Which one is slower?

4

I am running Lubuntu and ā€˜lsb_release -aā€™ gives me:
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 19.10
Release: 19.10
Codename: eoan

I am not using the stock kernel though, I am running the latest Liquorix kernel v5.5.0-7.1.

5

Video card B has less than stellar performance and it is especially noticeable using OpenGL.

6

And considering the kernel, not the desktop environment or the applications, is responsible for controlling the GPU, what makes you think thatā€™s not the problem? I would go ask at Liquorix. Alternately, go try the stock kernel and if itā€™s a problem, report a bug in Launchpad. In that case, it will not be a Lubuntu problem, but one that affects all Ubuntu flavors.

1 Like
7

Turns out, same results using the stock generic kernel as well.

8

So Iā€™d file a bug against the kernel in Launchpadā€¦ or given the fact that it might be the kernel in general, upstream!

9

So I was poking around and came across this:

http://forums.debian.net/viewtopic.php?f=6&t=77939

I read it and tried:

ā€˜vblank_mode=0 glxgearsā€™

The problematic video card ran full speed:

ATTENTION: default value of option vblank_mode overridden by environment.
37937 frames in 5.0 seconds = 7587.264 FPS
34374 frames in 5.0 seconds = 6874.700 FPS
38566 frames in 5.0 seconds = 7713.166 FPS
53974 frames in 5.0 seconds = 10794.649 FPS
54843 frames in 5.0 seconds = 10968.484 FPS

10

Well I think I have found a workaround. If I prefix problematic apps and games with ā€˜vblank_mode=0ā€™ all is well. I do not know if this is proper but it works. Thank you everyone for the help!

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11

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