I recommend installing the graphics driver ASUS provides in their website. The drivers they provide have been tested and validated to work fine in your computer. The drivers we have in our website are generic. We cannot guarantee those drivers will work fine on every OEM system. this is the link to ASUS website https://www.asus.com/Notebooks_Ultrabooks/ASUS_ZENBOOK_UX31E/#support_Download
I recommend you uninstall the driver from Programs and Features in Control Panel first and then install the driver from ASUS website.
thanks for the tip, but it's the same problem with the original ASUS driver. Could this Intel Inf Package causes the problem too? I installed it with the inf utility tool from the download-center - its the newest version for my plattform.
In safe mode, I don't have any bluescreen problems with standby-mode.