x301 external monitor can't go above 1440x900......help!

[bfeeny]

I am running an x301 which has Intel GMA4500MHD graphics. I am using Windows 7. All drivers and BIOS have been updated to the latest.

When I connect the x301 to my Vizio VF550M HDTV via a DisplayPort to HDMI adapter, I can only goto 1440x900. This is in clone or extended multiple monitor modes using either the Windows video control panel or the Intel control panel. If I run the external monitor as a single display it lets me goto 1920x1080 as well as numerous other resolutions above 1440x900. My Macbook Pro can connect via MiniDisplayPort to HDMI just fine to my Vizio TV and get full 1080p resolutions.

Does anyone know what I should check to see why this is? I see several people claim they run external monitors at many resolutions above 1440x900 or even above 1920x1080 in multiple monitor mode with no issue. There is no specific "driver" for my TV, Vizio does not put one out, and their FAQ says you do not need a driver, so it just shows up as a generic device in Windows Control and in the Intel Control Panel it shows up as VF550M which is the correct model. It does not allow me to change the refresh either.

Any ideas?