Latest config tool puts my screen slightly off to the right, just slightly when in workbench.
The first version of the config tool worked 100%, so will try going back to that.
Don't get the corrupt graphics as with the original core at 1024x768 @ 60 if I change this to 75 graphic corruption problems.
800x600 works great for games/whdload, although I can't get any resolution lower than that with the two newer cores but could with the original core. With the latest ones I get a black screen, and the monitor reports out of range.
My machine is a PAL machine.