ext2 versus ext4
 

Does the ext4 file system cause continuos updating of the hard drive?
I had puppyLinux installed with the ext4 system and no recommended setting could stop drive operating every 30 secs.Tried everything.Now with Zenwalk on ext2 it's quite.

Yes, in a nutshell the main difference between ext2 and ext3/4 file systems is that the later use a journal. A journal keeps track of changes before committing to the main file system and the commit interval default value is 5 sec. Journals help the file system come back online faster in case of a power failure and also help to prevent date loss and corruption.

Once you changed distro all bets are off. There is no way I can image you could easily narrow this down to ext2 vs. ext4. Distro devs make all sorts of decisions about what to/not include in the final package. Including such things as desktop options, I/O scheduler, (background) file indexing ... - as well as mount options.

Have you converted that ext2 to ext4 (on Zenwalk) to compare the effect ?.