Apart from users mentioning it in the forums here, I've only found one instance where this was mentioned, and that was in German. From the Gamestar article : (translated): "Divinity 2 is set on a strongly revised version of the Gamebryo Graphics engine, which was already used in Oblivion."
So, by 'strongly revised' I guess we can assume it will be optimized and have the wrinkles smoothed out.
