I wouldn’t have thought, but the VGA cable might be the cause why your computer doesn’t correctly recognized your monitor.
It was driving me crazy. My MacBook wasn’t able to use my sister’s display with its native resolution. I tried loads of stuff to get it working. I really needed to use the display. At one point I just switched the cable. And it worked!
Who would have guessed that a plain and stupid cable can be the cause of such trouble.