Xeon processors are best for server applications. Not necessarily designed to play games. That said, Xeon processors have been around a long while. Can you provide the actual model # of the specific processor you have? Xeon is a name for the model series (which has been around several years). The question is whether this is newer generation, old generation, etc.
And 2.8GHz is fairly slow these days. Some Xeon chips (old ones) are single core processors. Some may be dual, some quad, etc.