Don't look at how it runs right now, look into the future. In the future, if you got the 3700+ it would run dual core programmed games slower because they are trying to utilize 2 cores. If you get the opteron, the games are going to be programmed to run very will on both cores making the system very efficient. The opteron will run lag free for a lot longer time.
Sorry if that got a little confusing, I'm not that good at explaining things very well.
Sorry if that got a little confusing, I'm not that good at explaining things very well.