suspend hibernate

Hi I am quite chuffed because the laptop i am now using seems to have suspend with acpi working, but i am not totally sure. If i close the lid and open it after 20 minutes i get a locked password screen but my Zz light on the laptop is not on. When i manually suspend to disk it goes through the motion of suspending and seems to suspend, just my Zz light does not come on like it did with FC 3 before and that would freeze when i unsuspended. How can i be sure my computer is suspendig ok ? Suse looks great btw and even my modem works on my Acer 1362LC