System runs really slow and Mixxx takes up 100% CPU on Windows

Bug #252970 reported by Sean M. Pappalardo on 2008-07-29
This bug affects 1 person
Affects Status Importance Assigned to Milestone

Bug Description

Mixxx 1.6.0-beta4 pins the processor on startup, even preventing mouse movement for 10 seconds at a time! (This is not a problem in 1.6.0-beta3, but still a problem in 1.6.1.)

Tested on a Compaq Presario R3306US laptop: AMD Athon XP-M with nVidia GeForce 4 Go 440 video card & nVidia drivers, Windows XP Home SP2. (On Debian Lenny on the same machine, this is not a problem.)

Workaround: Switch to the Simple waveform view. Options->Preferences->Interface->Waveform Display, set to Simple
(Since it's really hard to move the mouse, use this key sequence: CTRL-P, crsr down x3, TAB x5, crsr down, enter, Alt-F4.)
Then restart Mixxx.

Theory: Waveform display uses OpenGL. Cards that don't support it use the main CPU, bringing it to its knees.

description: updated
description: updated
description: updated

This is still a problem in 1.6.1. Can't we add some OpenGL hardware detection code that reverts to the rendering used in 1.6.0-beta3 if the new method is not supported by the hardware? Please?

...or at least add a third "Old waveform (for no h/w GL)" or "Software waveform" option in Waveform Display?

RJ Skerry-Ryan (rryan) wrote :

You're correct that cards that don't support OpenGL use the main CPU. However, this waveform viewer in 1.6.0b3 (old waveform viewer) required OpenGL or it wouldn't work at all. In beta 3 were you able to use the old waveform view successfully?

Adding the old waveform viewer back as an option is not possible because the re-write changed Mixxx a good deal. I am looking at ways that we can switch back to the 'streaming' functionality of the old waveform viewer (i.e., not precomputing the entire waveform) for low power CPUs like netbooks. This would help alleviate some of the slowness here.

BTW, I tested with 1.6.1 today in Linux on the same system and it works fine (even to 10ms latency.) So something else is going on that's OS-specific.

description: updated
ironstorm (ironstorm-gmail) wrote :

If you want to verify that it's waveform related, try using an old install of Mixxx 1.5.x. That uses the old waveform, I suspect the performance will not be any better though, because as RJ said the old one used OpenGL too.

Since there is no reason why a GeForce 4 card can't do basic OpenGL (I used to run XGL on a GF4 Ti4400 on Dual P3 800 with no probs), I suspect there is a problem with the video driver or the windows installation, especially because it works on Debian w/ same video hardware.

If the CPU was maxing out when a song loads, I would suspect that is either BPM detect or waveform generation which are issues known to effect slower hardware.

I force-installed a newer version of the nVidia drivers (from nVidia's site, not from laptop manufacturer) and the problem is gone.

Invalidating since it was due to video driver. Should add something to the Wiki about this.

Changed in mixxx:
status: New → Invalid
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