yea looks like the same issue i had with my Samsung T24A350,
in which VGA looked better than HDMI , required about 6-7 hours of messing with various settings till i got it fixed, 1 to 1 mode didnt fix it required alot of messing around finally uninstalled the Samsung EDID info replaced with generic and viola worked, not sure that will help the OP, but it fixed all my Samsung woes. also allowed for better color calibration as my samsung liked to look more sepia than correct lol
Thanks for the response. Okay, so you use VGA instead of HDMI and it's fixed for you?