In this article we will measure how much power low power CPUs, such as the Opteron 2377 EE and the Xeon L5520, save compared to their "normal" siblings. We will use our own virtualization benchmarks to make it a bit more realistic than SPECpowerjbb. Maybe the most important question: is the performance/watt ratio of a more expensive, low power server CPU really better?
Focusing on the CPUs alone would be a missed chance. Whether you need 10 or 8 servers to consolidate your applications does not depend solely on the CPU power, but also on the amount of memory you can place inside your server, the amount of expansion slots, and so on. In addition, power consumption does not depend solely on the CPU but also on how clever the server engineers design the server chassis and power supply. We assembled four different servers from three different manufacturers. Every server represents a different take on how to reduce power and CAPEX costs. Let us see how much sense it makes to invest in low power servers with low power CPUs in a virtualized environment.
Does that mean this article is only for server administrators and CIOs? Well, we feel that the hardware enthusiasts will find some interesting info too. We will test seven different CPUs, so this article will complement our six-core Opteron "Istanbul" and quad-core Xeon "Nehalem" reviews. How do lower end Intel "Nehalem" Xeons compare with the high end quad-core Opterons? What's the difference between a lower clocked six-core and a highly clocked quad-core? How much processing power do you have to trade when moving from a 95W TDP Xeon to a 60W TDP chip? What happens when moving from a 75W ACP (105W TDP) six-core Opteron to a 40W ACP (55W TDP) quad-core Opteron? These questions are not the ultimate goal of this article, but it should shed some light on these topics for the interested.
http://it.anandtech.com/IT/showdoc.aspx?i=3606&p=1
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