Tweebel is right on the money. The xp2500 is better than the sempron 2600. The xp-m2500 is a little slower than the xp2500, but runs cooler, and OCs better. If you dont OC or UC, the xp2500 is the best of the 3. If you OC, or UC the xp-m2500 is for you. If you can get a deal on the sempron, it's not a bad chip, just not as good as the other 2.