Yes,
Whether the Registry tweak is needed in all cases, is as clear as mud Jim.
This is what WD says about it.
http://wdc.custhelp.com/cgi-bin/wdc....MQ%2A%2A&p_li=
They imply that it must be enabled manually after SP1 is installed. However, as you say, XP now might do it automatically. With all the updates flying out of MS, the issue may have been addressed.
As you say, it may be trial and error.
bo kingdon
Try the Registry tweak and see if that helps.
HTH