I got a great tip at techsupportforums.com to try a free tool called MSC
Standby Tool:

http://slicksolutions.eu/mst.shtml

It was originally for MSC but works for several OS's and can do a lot to
resolve the evidently very prevalent problems encountered with reduced
power states.

It can be run as an exe or installed from the exe's GUI, for expanded
control. I haven't installed it yet, but ran it and went into S3 Standby
and successfully woke the system up after 49 minutes, which I think is a
record. I don't feel so bad now that I realize that the problems I've
been having are commonplace and that there are things I can do to
resolve the difficulties. This tool looks terrific.