It seems I can't find the thread where I posted the link before.. but the Sempron beats the Celeron D and here is the evidence:
Let's look at the thermal specification of both rivals first: The maximum thermal loss of the 2.0 GHz Sempron (2800+) is 68.3 W, while the Celeron D is specified at 73 W and thus less efficient in terms of power/performance.
After a short look at our benchmark results the conclusion is clear: AMD's Sempron is able to outperform Celeron D in most applications. In addition, motherboards based on the nForce2 IGP chipset offer more graphics performance than Intel's 865G platform at a similar and sometimes lower price - even though we're talking about a pathetic level of 3D experience here.
But that is not the reason why value systems are bought. Price is what counts and this is why AMD is making extensive use of its proven technology. In order to grow its business, AMD needs to continually draw maximum value out of its existing products and to transfer that value to its customers. This is what AMD accomplished with the Sempron, by combining existing AthlonXP and Athlon64 features to fulfill a specific market sector demand, which in this case is the value processor market.