That depends on whether you're using an official build or an SVN compile.
Anyways one of them should actually be slightly faster on your system as your Processor has well past SSE2, so you should try the build that has SSE2 in it's name, the non-SSE2 one is for older processors that don't have SSE2.
The third one is most likely one which runs a command console in the background which aids in finding out what error just occured (basically it contains debug info that's useless to the common DeSmuME user unless a dev requests it), but whatever package you got of DeSmuME might contain another type of build.
Anyways one of them should actually be slightly faster on your system as your Processor has well past SSE2, so you should try the build that has SSE2 in it's name, the non-SSE2 one is for older processors that don't have SSE2.
The third one is most likely one which runs a command console in the background which aids in finding out what error just occured (basically it contains debug info that's useless to the common DeSmuME user unless a dev requests it), but whatever package you got of DeSmuME might contain another type of build.