I have a reciever that is capable of 7.1 surround. My previous graphics card showed the valid choices.
The Intel HD Audio only shows 5.1 surround as the best option. There is no 7.1 option.
This is Intel HD 4600 on windows 7,8 and 8.1
This will depend on the port that is being used and what the motherboard manufacturer or computer manufacturer has enabled for that port in particular. So in this case, you should check with your Original Equipment Manufacturer or motherboard manufacturer to see what sound features will be supported by that product and through which interfaces will be supported.