Hi,
I've been using RME Raydat for avout 2 years, and it works very well for
me.
First of all I only use Jack to make all my audio stuff.
I'm using Fedora 20 for x86_64, stock kernel with some configuration; my
kernel command line has these extra options: pcie_aspm=off threadirqs
i915.enable_rc6=0
I added the rtirq package to set irq priorities. I'm running jack at 60
priority 512 buffer 2 periods 44100 sampling frequency.
I get rare XRuns, usually when I start or close programs.
I use the builtin RME matrix mixer to monitor incoming signals, so
latency is not important to me.
When I use some virtual instrument I set the buffer at 256, I get some
more XRun of course... I also switch to the performance governor in that
case.
Pulseaudio is disabled.
And no custom ALSA configuration at all, IMHO Jack is a must to work
with multichannel cards.
Ciao
Guido