Hi :) I set up CPU frequency scaling as needed and run the Jack MIDI latency tests again. I suspect the nouveau driver still is broken [1]. There are still Xruns and there's an absurd high peak. Now I need to get my nvidia/nv set up back, but this script https://wiki.archlinux.org/index.php/NVIDIA#Switching_between_nvidia_and_nou... is useless, because of [spinymouse@archlinux ~]$ cat /etc/modprobe.d/modprobe.conf cat: /etc/modprobe.d/modprobe.conf: No such file or directory [spinymouse@archlinux ~]$ grep MODULES /etc/mkinitcpio.conf # MODULES # MODULES="piix ide_disk reiserfs" MODULES="" # 'filesystems' is _required_ unless you specify your fs modules in MODULES ## This setup specifies all modules in the MODULES setting above. Since the nv driver still is installed, I also tried to blacklist nouveau, but starting GDM always failed. I prefer not to restore Arch from a backup. There must be a way to get rid of nouveau and get nv and nvidia working again. At the moment I'm stuck. Regards, Ralf [1] [spinymouse@archlinux ~]$ cpupower frequency-info | grep The\ gov The governor "ondemand" may decide which speed to use [spinymouse@archlinux ~]$ sudo cpupower frequency-set -g performance [spinymouse@archlinux ~]$ cpupower frequency-info | grep The\ gov The governor "performance" may decide which speed to use [spinymouse@archlinux ~]$ uname -r 3.4.4-rt14-1-rt [spinymouse@archlinux ~]$ hdspmixer Card 0: RME AIO S/N 0x579bcc at 0xfdbf0000, irq 18 Card 1: TerraTec EWX24/96 at 0xbf00, irq 20 Card 2: TerraTec EWX24/96 at 0xbb00, irq 21 [spinymouse@archlinux ~]$ sudo chgrp audio /dev/hpet [spinymouse@archlinux ~]$ sudo chmod g+rw /dev/hpet [spinymouse@archlinux ~]$ sudo modprobe snd-hrtimer [spinymouse@archlinux ~]$ /etc/rc.d/rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 59 FF 90 - 130 0.0 S irq/8-rtc0 300 FF 85 - 125 0.0 S irq/18-snd_hdsp 335 FF 80 - 120 0.0 S irq/20-snd_ice1 338 FF 79 - 119 0.0 S irq/21-snd_ice1 116 FF 70 - 110 0.0 S irq/19-ehci_hcd 118 FF 70 - 110 0.5 S irq/16-ohci_hcd 121 FF 69 - 109 0.0 S irq/17-ohci_hcd 125 FF 68 - 108 0.0 S irq/17-ohci_hcd 57 FF 65 - 105 0.0 S irq/1-i8042 20 FF 50 - 90 0.0 S irq/9-acpi 105 FF 50 - 90 0.1 S irq/22-ahci 123 FF 50 - 90 0.0 S irq/18-ohci_hcd 127 FF 50 - 90 0.0 S irq/18-ohci_hcd 130 FF 50 - 90 0.0 S irq/14-pata_ati 131 FF 50 - 90 0.0 S irq/15-pata_ati 267 FF 50 - 90 0.0 S irq/7-parport0 293 FF 50 - 90 0.0 S irq/22-firewire 330 FF 50 - 90 0.0 S irq/18-nouveau 588 FF 50 - 90 0.0 S irq/43-eth0 3 FF 1 - 41 0.0 S ksoftirqd/0 11 FF 1 - 41 0.0 S ksoftirqd/1 [spinymouse@archlinux ~]$ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256 jackdmp 1.9.8 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:1-1 HDSPMx579bcc MIDI 1 1 out" "system:1-1 HDSPMx579bcc MIDI 1 1 in" Reported out-port latency: 5.33-5.33 ms (256-256 frames) Reported in-port latency: 5.33-5.33 ms (256-256 frames) Average latency: 11.69 ms (560.52 frames) Lowest latency: 11.65 ms (559 frames) Highest latency: 11.76 ms (564 frames) Peak MIDI jitter: 0.10 ms (5 frames) Average MIDI jitter: 0.02 ms (0.04 frames) Jitter Plot: 0.0 - 0.1 ms: 8189 > 10 ms: 3 Latency Plot: 11.6 - 11.7 ms: 7906 11.7 - 11.8 ms: 283 > 21.6 ms: 3 Messages sent: 8192 Messages received: 8192 Xruns: 3 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:2-1 TerraTec EWX24/96 MIDI 1 out" "system:2-1 TerraTec EWX24/96 MIDI 1 in" Waiting for connections ... Waiting for test completion ... Reported out-port latency: 5.33-5.33 ms (256-256 frames) Reported in-port latency: 5.33-5.33 ms (256-256 frames) Average latency: 11.69 ms (561.05 frames) Lowest latency: 11.40 ms (547 frames) Highest latency: 11.76 ms (564 frames) Peak MIDI jitter: 0.35 ms (17 frames) Average MIDI jitter: 0.00 ms (0.04 frames) Jitter Plot: 0.0 - 0.1 ms: 8191 0.2 - 0.3 ms: 1 Latency Plot: 11.4 - 11.5 ms: 1 11.6 - 11.7 ms: 7704 11.7 - 11.8 ms: 487 Messages sent: 8192 Messages received: 8192