[[ EDIT: Solved! It turns out that the Auto Image Adjust on my monitor is capable of reinterpreting the pixel clock to get the best possible image out of the analogue VGA connection (pretty smart design!). One of the test patterns I used to auto-adjust had some weird lines and patterns, which apparently confused the software. I found out when I did a factory reset of the monitor and saw that the pixel clock was correct; after Auto-Adjusting to the calibration pattern, it was off again. To correct, I merely readjusted to a different pattern, and problem solved. 17 AUG 2006 ]]
My custom DTD specifies a pixel clock of 146250KHz. This worked fine for a few minutes. After setting the system to Standby, I noticed a bit of softness in the display upon resume. The monitor now reports a pixel clock of 146400KHz, and this is backed up by the soft spot down the center of the panel, and some ugly moire pattern that wasn't there before. A system restart did not help.