newbie with a problem..

[David Adler]

> Finally I got tired of this, reinstalled Ubuntu and got Jack and amSynth
> working together in real time (it took me a day and a half, but I managed
 have to work if possible. My laptop is an IBM Thinkpad T40, 1.50 GHz, and
> it!) Now the sound quality is beautiful... if I only open 4 or 5 instances
> of amSynth. But if I open more than that, my laptop makes a horrible noise
> and freezes, and the only way I can shut it off is to take the battery
> out.
>
No idea about the freezes, normally jack starts producing xruns when
overloaded, but does not freeze the hole computer

> I spent some time trying to figure out why this happens and finally
> twigged that the Jack panel shows its CPU usage. When I play just one
> amSynth the CPU usage is 41%, and for 5 amSynths it's a massive 82%, which
> explains why my computer freezes. So it seems my computer just isn't fast
> enough to do what I want it to do :-(  So my questions is, is there
> anything I can do to fix this, short of buying a faster computer? Would it
> help if I got a better soundcard?

Geerally, you could increase the number of frames per period in the
settings-window of qjackctl to reduce cpu-usage (and increase
latency).
AFAIK the soundcard has no/very little effect on cpu, so your options
are either trading off cpu-usage with latency (whitch is usually ok
for production) or spending money on a faster cpu if latency is a
concern.