The advent of dual-core and
quad-core processors in the x86 server market represents a
major change in how performance is delivered to IT organisations.
In the past, performance increases were delivered by increasing the
execution rate - the frequency - of the processors, and thus any
application would run faster on a faster processor.
This is not the case with
multicore processors.
For an application to enjoy increased performance, it must be a
"well-threaded" application. A well-threaded application is written
so that some of its tasks - ie. threads - can run concurrently on
multiple processor cores. If an application is not well-threaded,
then all the cores in the world will not give it more
performance.
The software issue around multiple cores will present a big
challenge, and there are good sources of guidance available online.
But it is not just software that will be potentially affected by
multicore x86 servers. The other item that has the potential to
change is buying behaviour.
In recent years, dual-socket configurations have been the sweet
spot in the x86 server market. In these configurations each socket
was populated with a single core processor, so for many years
dual-socket was synonymous with dual-processor. This dual-socket
configuration represented about 70% of x86 server shipments and
revenue in 2006.
Because of the volume of purchases, dual-socket configurations
have had the best manufacturing economics and the best price
competition in the x86 server market. As a result, most enterprises
have standardized on dual-socket configurations for their standard
x86 server purchase.
The introduction of multicore x86 processors has the potential
to change the market dynamics. In 2007, a dual-socket configuration
can contain single or multicore processors. This is equally true of
single-socket and
quad-socket configurations. For example, you can buy a
single-socket server with a dual-core processor or a dual-socket
server with two single-core processors. They are both
dual-processor configurations, which adds complexity to buying
decisions.
Server suppliers are not making these new decisions any easier
either. Some suppliers are continuing to suggest that dual-socket
configurations are the wisest buy, while others are suggesting
users move up to quad-socket configurations to better support
larger workloads driven by virtualisation. Some suppliers are even
suggesting that you downsize to single-socket servers and increase
the core count of the processors.
On this last point, it will, in some cases, be possible to use
single-socket configurations in place of dual-socket
configurations, but IT directors would be wise to exercise caution
here.
Single-socket configurations often do not offer the same
redundancy capabilities for fans and power supplies and often
cannot be configured to handle the same amount of memory and
input/output (I/O) as dual-socket servers. A single dual-core
processor does not deliver the same performance as two single-core
processors.
However, if you have been using single-socket configurations
successfully, you can certainly continue using them.
For organisations that are operating fewer, larger servers, the
higher costs for quad-socket configurations may be offset by
operational efficiencies. But denser server workloads involve more
complexity, and more complexity may lead to administrative
inefficiencies.
Be careful that you are not paying more in hardware and
operational costs.
The full Gartner
report >>
Rebirth for
the x86: what to buy >>
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