Instructions For NVIDIA Cards
First, set your desktop to horizontal span, so that X2 will detect the extended resolution upon startup. We recommend creating a new nView profile for this purpose (see above).
After starting the X2 launcher, the configuration dialog will offer the new, "wider" resolutions. To prevent getting a distorted image, we recommend choosing a horizontal resolution that is twice that of the "normal" one, for example 2048x768 (1024 horizontal per monitor).