The answer was simple: "You cannot compare a truck with a sports car." The question? "What is point of the hex-core Xeon MP now that we have servers based on the Xeon 5500 series?" The excellent performance of the new Xeon DP platform has put Intel's own quad socket platform in an uneasy spot and the marketing people now have to resort to "fuzzy logic" to combat the feeling that the Xeon MP platform is obsolete since the end of March 2009. Comparing the dual socket Nehalem servers with sports cars and the heavy quad socket "Dunnington" systems with trucks might look like a decent analogy at first, but both the DP and MP platform are made for the same reason: do your processing work. There is nothing that prevents you from using a Xeon DP X5550 server instead of a Xeon 7460 one as a database backend: they can perform the same tasks. However, moving your furniture with a Lamborghini instead of a truck might prove to be quite a challenge.

Does it matter for you, the IT professional? Yes, and the reason is once again… virtualization. Choosing between a dual and quad socket server used to be simple: use the latter for the heavy backend applications, the former for everything else. But do you build your virtual infrastructure on top of quad socket or dual socket machines? The dual socket servers are much cheaper than the quads, you can easily get two and still save some money compared to buying a quad machine. However, two dual machines have four power supplies if you want redundancy, and when running 10 critical applications on a machine redundancy is something you cannot afford to ignore. Most quad socket machines are more redundant and reliable. Since the quad market is less ruled by price/performance and slower to evolve, manufacturers can afford to spend more time and money working on the reliability of their machines. One 2U quad machine will also have more expansion slots than two 1U dual socket machines.

Do you get a few quad socket machines or (slightly less than) twice as many dual socket servers? It is not as clear cut a decision as it used to be. This article will compare the power and performance of the current AMD and Intel quad and dual platforms, giving you some of the information you need to make a well informed decision. Please share your own experiences with the dual and quad socket question, we are eagerly awaiting them.