Powermanagement doesnt suspend correctly

Can anyone tell me the difference between calling echo mem > /sys/power/state and pm-suspend?

pm-suspend often does not suspend my machine, whereas **echo mem > /sys/power/state **usually always works.

I think **echo mem > /sys/power/state **just skips the execution of some scripts or is there more difference?

When suspending does not work, I usually see this message in /var/log/pm-suspend.log

NETWM: Warning readIcon() needs buffer adjustment!

When I google this message it seems to be KDE related.

So, anyone a clue about this warning message and the difference of the above commands?

Thanks

By the way, powermanagemt also effects desktop systems and servers, I donĀ“t think it should be only in the laptop forum.