So, I did some test of my new Entroware Apollo and got some nice results. Running on GNOME 3, realtime kernel and nothing much more (not even by boosting CPUs) the system performances are already very good, although none of the stability definitions have been respected.
But let’s go with order.
First of all the test bed. I booted into my Arch Linux + Gnome 3 and hooked the sound-card (Focusrite Scarlett 2i4) to the USB 2 port and the midi controller (M Audio Keystation Mini 32) to the USB 3 port.
Audio optimization is achieved by rtirq, pam, noatime mount option, low swappiness and RT kernel.
The procedure was a trial and error of jack setups until a xrun-free one was found. Then, latency assessment.
The latency has been measured using jack_iodelay with a feedback loop from output 1 to input 1 of the soundcard. This page has been followed, but resistors are not necessary. Just set preamp and output to reasonable levels. Start from all knobs to zero and slowly raise, don’t risk to overdrive the card! Also, use the jack_iodelay command instead of jack_delay. A succinct How-To is presented here.
The xrun frequency has been measured recording with Ardour from all the inputs while supplying monitoring to all the outputs. Ten takes one minute long each have been used. All the data have been put into the definition in this post.
The results are as follows:
/usr/bin/jackd -t5000 -dalsa -r96000 -p128 -n3 -D -Chw:USB -Phw:USB
With this configuration the xrun frequency is 0 Hz (no xruns), but the latency is a little more than 8 ms, failing to reach the conditions of the Lowlatency definition. Lowering the Periods/Buffer lowers the latency, but it is never stable enough to record with Ardour: xruns pop up a lot. However, it is stable enough to use Guitarix and Calf, making possible to use the machine as a Lowlatency effect processor.
As a conclusion, the results are impressive. In fact, with a fairly heavy (and, to be honest, even a little bit bloated) Desktop Environment, without killing unused services and programs, without acting on CPU governors and not even by killing pulseaudio, the computer operates very nicely if using an RT kernel. So, if the remaining adjustments are done and a lighter DE is installed, very good performances should be achieved. However, I don’t want to install an alternate DE at this moment as I like my system simple. Also, I don’t want to kill other services as I want my setup to be multipurpose. Finally, I prefer to save battery and use the ondemand CPU governor. As such, I will left my computer as it is for now.
If you wanna see it in action, check my YouTube channel.
A comparison with a Mac Book Air can be retrieved here.
Here a review of the laptop performances after a year of usage.
After I got few comments asking for more info, here few pictures showing the laptop construction.