Black Border at Boot Screen


Jan 4, 2010
Hi all, when my monitor is connected to my HD 5750 via DVI cable i see a black border (about an inch thick) around all corners of my screen until I see windows login screen. I also see this border in safe mode and bios settings screen (the resolution is fine). However there is no such border if I connect it with VGA cable. My card natively support vesa resolution of 1920x1080 and so is the resolution of my LG monitor. I know technically its called under-scanning/scaling but how do I fix it. ATI CCC only helps after windows has booted. I need something that can fix this under scanning issue before winnows has booted. I can't play with monitor settings on digital input. Is it my gpu or monitor?
Thanks in advance