Is it possible for Mac (with the Aspyr port) and Windows version of Civilization V to participate in a multiplayer game together ? Or is the only option to run the Windows version on the Mac (either via Bootcamp, Parallels, WINE, ...) ?
Civilization V for Mac does support playing multiplayer with PC users, but the Mac version frequently lags behind the PC version, which prevents Mac and PC users from playing together. Generally, when Aspyr releases a patch that re-enables cross-platform multiplayer, they make a note of it in the patch notes.
Bah... versions keep rolling out but none have sync the platforms together yet for multiplayer. I finally installed it on my old PC just to play with a friend but i'm not sure it was worth it as my PC system is old and outdated creating a lot of lag during IP play. You would think it would be easy to get the versions to coincide but apparently not.