Dear Maarten, thanks for your reply. I definitely will put in more memory if the customer pays ;)

Instead of memtest, just running 'top' or 'free' would have told you what's wrong...

if top or free had told me this I wouldn't have asked

Spamd and amavisd will quite easily kill your machine seen as it has only 256 MB. Just one mass-mailing (inbound of outbound) will take care of that. Been there, done that, got the T-shirt...

It can't be easy as that, because the machine is up for almost half a year and only recently started to behave like this. On top of that, for three weeks in a row the customer sent tons of mails from this server (some promo or other) and nothing happened. Usually this server takes about 1000 mails inbound and about 500 to 1500 mails outbound in stride without so much as a whimp. All the time this happened for the last few days the load never reached 4.00 which I would've expected. And all the time more than 30% memwere unused... That's why I asked. Regards Wolfgang