You can view the differences between the DN and GX configurations by looking at the Product Brochure for the 7750 (PDF File).
There have been some issues with the default driver that is installed in Windows 7 for some of the Phaser products. Have you tried downloading a new driver from our website and doing a clean install? You should be able to download Windows 7 drivers from here.
Once the driver is downloaded, the first thing you will want to do is completely remove the driver you currently have installed. Directions for doing that are located here.
Once you completely uninstall the driver, you can follow these directions for installing the new driver you have downloaded.
If you have any issues, please do not hesitate to call in for support at 800-835-6100.
I have a Phaser 7750GX PS on Windows 7 Ultimate. I'm trying to print PDF and Publisher files in automatic duplex, but they come out very small and in the wrong orientation. I've tried resetting software, hardware, turning off and on, and reinstalling drivers. Sometimes when choosing DN it comes out in grey scale; is that a bw driver?
Also confusing as to model and driver - one info source says it's a GX and one says DN...what's the difference? I've successfully printed out many duplex and single-sided documents in the past.
Thanks for any tips, as I'm preparing for a conference and need the printer to work.