Free RAM disappears - Memory leak?

Solution 1:

1. The huge number of open files is a good clue that something is going wrong. My guess would be some KDE system daemon.

2. Open a console and run "top". Then use < and > to change the sorting column to VIRT or RES and see which programs are using the most memory. A memory leak will show up as a massively inflated virtual memory use, as once the pointer to the leaked memory is lost it won't be used and will be swapped out. Also run "lsof" and look for a process with lots of open files, since this seems to really be a file descriptor leak.

3. Track down the program and report a bug.