LCD not going into power save mode...

[geecee]

XP Home SP2, older Catalyst drivers (don't remember the version off the top of my head), Radeon 9100 64MB & a 22" Envision G22LWk (just added. probably just a generic TN panel). No problems using the analog connections but using DVI connections, the monitor never powers down. The screen blinks when the monitor turn off time is reached (as set in Power Options). It looks like it's going to sleep, but then comes back on a few seconds later. I'm not using the latest Catalyst drivers but they are probably from about 6 months ago. Didn't see any definitive answer in the google results either. Anyone have any ideas/ever seen this before? TIA.