2.4.9-ac1 slight RT sluggishness

Just collected all the facts in a bunch:
1. There is a svgalib fast-action game called koules.
Koules intro eventually delays by about 1/10 sec, and it is _visible_.
2. Again these delays while playing music: mpg123+esd.
3. Again these delays are in sync with gpm mouse stalls.
I.e when sound stops for its 1/10 sec, mouse stops to respond too.

a) mpg123 is reniced at -20.
b) "find /" doesnt seem to affect this behaviour.
c) it is a somewhat flashing effect: one minute it triggers each 5 secs or so, next 10 minutes i do not see it.
d) CPU load is in its right limits.

p166/24M/2.4.9-ac1/2.95.3

cheers,
Sam