bassfisher6522, thanks for the reply.
1. Went into the nVidia control panel, and both setting are set correctly. The primary screen (samsung) to "recommended", the secondary screen to "native"
2. If i plug the acer monitor in by itself (so computer runs only the one screen), the resolution is fine. However, the problem only occur when both are plugged in at the one time.
3. Refresh rates:
Samsung (primary) is 60Hz
Acer (secondary and problematic!?!?) is 64hz