First, please accept my gratitude for a very useful application. Thank you.
That said, I've got guitarix (latest git as of 9/9/13) running on an Intel P4 Mobile 1.8Ghz notebook with 1G RAM. Not the fastest hardware, but in my mind, certainly adequate for the application domain.
I'd be running on a Raspberry Pi, but I'm having problems with my chosen USB audio interface on the Pi hardware. That is another story. :-)
This notebook is running Debian Wheezy. The issue I'm about to describe exists in the Debian package of guitarix (0.22.4-1) as well, but it seems more frequent with the latest git.
When using my MIDI foot controller's expression pedal to change the pre and post gain settings, occasionally, the audio will break into static for a split second. With the latest git, I noticed that the server and the GUI client had been abstracted (hurray!), so I decided to see if that offered a different result. The server (guitarix -N) did not exhibit the issue. So I figured I would try the GUI client with the server, since I use Live Mode. With the GUI client running, the issue presented.
Using top to monitor the processes, I could clearly see it was the GUI client process that increased substantially in CPU usage when the expression pedal was in consistent use. The server process stayed around 25%-30%, and the GUI process went from 20% to the 50%-60% range.
Also, I will mention that in Live Mode on latest git, the control parameter meters don't respond as smoothly to value changes as they do in the Debian package.
I would appreciate any help you could offer in troubleshooting and resolving these items.