Disk Cache: Out of interest what does KDE store there?
 

i dont really care about RAM usage
i actually have always liked that Linux uses my Ram efficiently
and only falling back on Swap in desperation

The disk cache in Kcontrol Memory Info
seems to fluctuate greatly to suit my memory usage.

currently diskcache is 1.4GB

what is generally in the diskcache?

/var/tmp/kdecache-`whoami` subdir like `http; stores cache of webpages, `favicons' for site's favicons, `help' for kde help file index.

does that mean i can symlink certain objects to /var/tmp/kdecache-
for chance to be cache?

say my firefox cache?

No, they have diffrent cache method.