Turning on V-Sync, with your gfx card will not help. Sorry.
A neat little trick to give you a little performance boost is to increase the CPU priority of the SH3.exe process from within the windows task manager. Set it to high after Alt+Tab from the main menu of SH3.
You can also double the amount of Virtual Memory on your system, this will help.
There are programs like Enditall & Xp Smoker which will manage the closing & restarting of programs that run in the background.
Also, make sure that you are not 'forcing' any AA or AF through your GFX card settings. Either turn them off or set them to 'Application Preference'.
Welcome to Subsim & enjoy the GWeXperience.
