I just took a quick look at Sony for your monitor: Sony eSupport - SDM-HS73 - News & Alerts
The drop down list under drivers doesn't show anything for Windows 7 or Vista.
I've at times used a generic video driver and did not notice anything inferior about it.
I guess you could experiment with an XP driver, maybe in compatible mode?
It's entirely possible Sony has quit driver development for this monitor and that you have no choice other than the generic driver you are now using.