Demystifying Hardware - SQL Server 2012 Internals and Troubleshooting - page 34

the last generation of Intel Xeon processors to use a symmetrical multiprocessing (SMP) architec-
ture, rather than a non-uniform memory access (NUMA) architecture, so it did not scale very well
when additional processor sockets were added to servers. The Intel Xeon 7400 series did not have
hyperthreading. Many four-socket servers of this vintage are still in use today, even though their
performance and scalability has long been eclipsed by modern two-socket servers.

By early 2009, you could get a two-socket Dell PowerEdge R710 with two, quad-core Intel Xeon
X5570 processors, and 144GB of RAM (with a total of 16 logical cores with hyperthreading
enabled). This system had four PCIe 2.0 expansion slots, divided into two

4 slots.
This provided a very powerful database server platform in a very compact package. Such a system
would have a Geekbench score of around 15,000. It used the 45nm Nehalem-EP family processor,
which had NUMA support. This was when the tide began to turn in favor of two-socket servers
instead of four-socket servers, as this system had enough CPU, memory, and I/O capacity to com-
pare favorably with existing four-socket servers. If you were concerned about 144GB of RAM not
being enough memory in the R710, you could buy two R710s, nearly doubling the CPU capacity
and the I/O capacity of a single R900. This assumes that you could split your database workload
between two database servers, by moving databases or doing something such as vertical or horizon-
tal partitioning of an existing large database.

8 and two

By early 2011, you could buy that same Dell PowerEdge R710 with more powerful six-core 32nm
Intel Xeon X5690 processors and up to 288GB of RAM (with a total of 24 logical cores with
hyperthreading enabled), and push the Geekbench score to about 24,000. This gives you quite a
bit more CPU capacity and memory than the PowerEdge R900 that you could buy in late 2008.
An R710 with those processors would give you the absolute best single-threaded OLTP
performance available until March 2012, when the Dell R720 with the 32nm Xeon E5-2690
became available.

In March of 2012, you could purchase a two-socket Dell PowerEdge R720 with two, eight-core
32nm Intel Xeon E5-2690 processors and up to 768GB of RAM (with 32GB DIMMs) and seven
PCIe 3.0 expansion slots, split between six

16 slots. This provides a total of 32 logical
cores (with hyperthreading enabled) visible to Windows, and this system has a Geekbench score of
about 41,000, a signii cant improvement over the previous generation R710 server. It also has more
memory capacity, better memory bandwidth, and much more I/O capacity due to the higher number
of improved PCIe 3.0 expansion slots. This two-socket system has a Geekbench score that is roughly
comparable to a 2011 vintage four-socket Dell PowerEdge R910 server that is using the 32nm Xeon
E7-4870 processor. We now have a two-socket server that compares extremely well with the latest
model four-socket servers in nearly every respect.

8 and one

This overall trend has been continuing over the past several years, with Intel introducing new
processors in the two-socket space about 12-18 months ahead of introducing a roughly equivalent
new processor in the four-socket space. This means that you will get much better single-threaded
OLTP performance from a two-socket system than from a four-socket system of the same age
(as long as your I/O subsystem is up to par). The latest model two-socket servers with the Sandy
Bridge-EP Intel Xeon E5-2690 processor compare very favorably to four-socket servers with the
Sandy Bridge-EP Intel Xeon E5-4650, and even more favorably to four-socket servers with the older
Westmere-EX Intel Xeon E7-4870 for all but the largest workloads.