Windows 7: Mstsc crashing due to graphics card?

I have just finished installing Windows 7 (x64) on a computer designed to be in the living room.
The computer has installed an ATI 4670 graphics card, running catalyst 9.9 drivers, the display being my full HD TV, attached over HDMI.

When trying to connect to this PC from another one (tested both Windows XP and Vista) at first attempt it will allow me to enter password, then die during the "Welcome" screen, effectively timing out mstsc. Subsequent connections will be blocked right away.
When logging in to the machine locally, at first I saw an error message, the desktop looking bad (the background was lost). After uninstalling catalyst control center the error messages stopped coming (as well local desktop looks ok after failed RDP attempt).
I have the suspicion, this problem being due to the graphics driver not managing switching resolution for the remote session as both computers trying to connect are not running full HD resolution.

Any help greatly appreciated.