MacBook GMA X3100 Dual-Head Max Resolutions

I'm currently running my MacBook (couple of years old Black Intel 2.2GHz with GMA X3100) with an external 17" monitor at 1280x1024.

I'd like to buy a new widescreen monitor running at full HD 1920x1080. Although this is within the maximum resolution of the graphics chip, will I still be able to run it simultaneously with the macbook's (1280x800) display? Or am I better keeping the lid shut and running a new monitor on its own?

Thanks in advance!

I have the same chipset in my MacBook (early 2008 white) and I run both a large wide screen Samsung monitor at its native resolution and the internal monitor at the same time. Most of the time I keep the MacBook in clamshell mode and just use the external. Works great both in Snow Leopard and dual booting to Windows 7 Home Premium.

Regards.