I have an SME Server 6.01 all patches (I know it is recommended to move on...)
However, it has been working well for what we use it for other than lateley it has come to a crawl a few times.
When I have seen this happen, and run top in it I see PERL at top of the list, consuming 98% CPU and approx 986M of ram.
A reboot sorts it out for about a week.
Can anyone offer assistanec on what to look for to sort this out?