Wow, we are 1/3 of the way through this series! Today’s post is “Classic Intel Xeon Processor Numbering Explained”. By “classic”, I mean Intel Xeon processors produced from about 2006 until April 2011 (when Intel introduced a new processor numbering system for new and upcoming processors).

Knowing how to decode the processor model number is a very handy skill to have when you want to be able to understand the capabilities, relative age, and relative performance of a particular processor. An example of an Intel processor number is shown in Figure 1.

Figure 1: Classic Intel Xeon Processor Numbering

Intel Xeon processor numbers are categorized in four digit numerical sequences, plus an alpha prefix to indicate electrical power usage and performance. The alpha prefixes are as follows:

   •  X   meaning Performance
    •  E   meaning Mainstream
    •  L   meaning Power-Optimized

The model number will start with a 3, 5, or 7, depending on the server form factor that the processor is designed for. If the processor number starts with a 3, it is designed for a single socket server,if it starts with a 5, it is designed for a two socket server, and if it starts with a 7, it is designed for a four socket or more server.

The second digit of the model number designates the generation, or relative age of a processor. For example the Xeon 5100 series was launched in Q2 2006, while the Xeon 5300 series was launched in Q4 2006, and the Xeon 5400 series was launched in Q4 2007.

For a more complete example, a Xeon X7560 is a high-end Performance processor for multi-processor systems, an Intel Xeon E5540 is a Mainstream processor for dual-processor systems, while an Intel Xeon L5530 is a Power-Optimized processor for dual-processor systems. The final three digits denote the generation and performance of the processor; for example, a Xeon X7560 processor would be newer and probably more capable than a Xeon X7460 processor. Higher numbers for the last three digits of the model number mean a newer generation in the family, i.e. 560 is a newer generation than 460, in this example.

In my opinion, you should always choose the Performance models, with the X model prefix, for SQL Server usage. The additional cost of an X series Xeon processor, compared to an E series, is minimal compared to the overall hardware and SQL Server license cost of a database server system.

You should also avoid the power-optimized L series, since they can reduce processor performance by 20-30% while only saving 20-30 watts of power per processor, which is pretty insignificant compared to the overall electrical power usage of a typical database server (with its cooling fans, internal drives, power supplies, etc.). Of course, it would be a different story if you needed dozens or hundreds of web servers instead of a small number of mission critical database servers, since the overall power savings would be pretty significant.