I've been trying to add two extra harddrives (180GB each) to my system which already have a 40GB (boot) and a 120GB.
The system finds the drives and I am able to partition, make a filesystem (reiserfs) and mount them.

The problem comes after a couple of minutes when I start using them.
They stop responding. If I was copying I get a "Segmentation fault".
If I happend to do a 'ls' the command never returns and I am not able to kill the command even as root.
The system also can't be shut down since the drives won't respond.

I've tested the drives and they work fine.
The whole HW configuration has been run with win XP without problems.
I've tried switching IDE ports and even used a Promise IDE expander.
The only time one of the drives works is if I use it as boot disk (which I don't want to).

DMA is on. UDMA mode 5 used.

Do anyone have an idea to what the problem is?