Is it possible to use a server to play games?

A server is much more a function of the software than the hardware. If the OS that you are using can play the game, then the "server" box that you are using can play the game.

With regard to the performance, with those specs, I would assume you have a very capable gaming machine, but that is more based on what you are comparing it to than anything else.

I never had any problems running games on server versions of Windows. One thing that could impact the performance of games on them is process priority setting. On server versions of Windows, it's by default set to background services and games like it more when it's set to programs option.

Another tricky thing is the sound service. It's disabled by default on Windows Server and some games may have problems starting if it's disabled or if the computer doesn't have sound card. Also even if there is a sound card, it may not have drivers installed, so be sure to check for that too.

Next point would be to install Direct X. Servers often don't have newest versions of Direct X installed and it's required by almost all games. Just get the newest DirectX End-User Runtime Web Installer (don't pay attention to claiming 9.0c version of DX. It should be installed on all supported windows operating systems, even if they claim higher version of DX).