hairy1: I am pretty sure the hard drive powers down. The first thing that I hear when turning the power back on is the hard drive spinning back up.
Yes I just opened this thread to say exactly that when I saw your post.
I set it to 'medium' and put it into standby (red light on front). It eventually powered the HDD down. So I take back my comment about real power savings, my confusion arose around the use of 'standby' in the email from Sky.
I struggled initially to understand their reasoning for standby times and inactive periods, but on closer examination it kind of makes sense to have longer inactive periods paired with the increasing time periods available for standby.
So now I am using the powersaving function I have another couple of (noddy type) questions:
Will it go into standby from its fully on state (blue light on)? I'm assuming yes as long as the 'No' conditions in the latter part of the email aren't met.
Does the inactive period start from the last IR command the STB receives?
What does the TLA (3 letter abbreviation) GPM stand for? I assume it is something to do with power monitoring.
Likewise when it talks about 'EPG activate standby' is that an additional step from within the EPG or is it just the column heading in the second table (column 2)?
This function doesn't affect MySky's recording capability in its 'down time' does it? I'm assuming not or it defeats the purpose of having a MySkyHDi.
Can I claim carbon credits for using the power saving mode?

If anyone from Sky reads these forums, could they use a different name for the powersaving mode than 'standby' like for instance 'powersaving mode'.