Hi Gary,
To provide appropriate information about the number of additonal sound cards that can added to OptiPlex 790, I need additional system information:
1. The system form factor (E.g. Mini Tower or Small Form Factor):
2. Version of Windows installed (E.g. Windows 7 Home Premium):
3. The name of the program that you use to select the sound cards:
Please reply to the post with the requested information.