[LAU] Ardour complains disk system can't keep up

[jim]

Hiya,
     I've got a Zareason media box
http://zareason.com/shop/MediaBox-5440.html
with 8 GB RAM running AVlinux (a debian flavor);
I use Ardour pretty much exclusively, that and
the vi editor.

     The system can record a single track with no
problem. It occasionally fails if I try to record
two simultaneous tracks. If regularly fails if I try
to record four or more tracks.
     The complaint is always that the disk system
cannot keep up.

Question: would just blindly replacing the spinning
disk with SSD be a likely fix and an overall good
idea?

Question: what info should I capture and email to
get appropriate help?

Question: what commands will yield useful info
for this diagnosis? (I like the command line but
forget which commands do what other than the
usual suspects for basic use.)

Hopefully, with thanks,
jim in SF