Ah ok. I see you did put 5.1 in your OP. I thought you might have been questioning if it would only support 5.1, and not 7.1.
You will have no problem getting 5.1 from any motherboard with SPDIF connection. In this case, optical. But it does depend on what you want to get 5.1 from. I see you have mentioned games, which will be a problem.
Getting 5.1 from DVD's or media with 5.1 Dolby or DTS tracks is not a problem. The software playing the media should pass on the 5.1 track to the receiver, to decode.
Getting 5.1 from PC games, is different though. DVD's for eg, come with a 5.1 Dolby/DTS track. Games, the majority of them at least, do not support Dolby or DTS. So a real time 5.1 encoder is required to encode the sound into Dolby, or DTS, so it can be passed via SPDIF, to the receiver to decode.
Some motherboards have these features, but it tends to be the more expensive higher end boards. That means buying a sound card with either DTS Connect, or Dolby Digital Live.
Cheapest sound card that has this capability, is the Xonar DS. It has DTS Connect. If you want Dolby, then the cheapest would be the Xonar D1/X.
Xonar D2/X and X-Fi Titanium have both.