I'm running 3.8 off the harddisk. With prolonged disk activity (such as md5sum of a huge file, creating a big file with dd such as making a persistent homedir, doing a diff on two huge files, etc), the system response time gets very slow. The mouse pointer is so erratic as to almost be unusable, and system response at the command line is significantly reduced. Running top from a tty, it looks as if X-related processes are suddenly using a fair amount of CPU, in particular kmix (of all things) which jumps up to 10% or more. Sometimes when I have done this a kernel process called [pdflush] eats huge gobs of CPU at 40% or more. Once the disk process ends, pdflush, kmix, and the other X processes drop back to normal.

None of this happened with 3.7

I realize this isn't likely to be a knoppix problem but I was hoping someone might be able to shed some light or give me pointers where else to ask about this.