Incorrect Bios Settings Can Reduce Database Performance [SQL Server]

Sam Saffron commented on my blog post asking me if I could share my thoughts on an issue he was experiencing. This was on a newly migrated SQL Server 2008 R2 database solution running on Nehalem Processor based CPUs. I went ahead and shared what I experienced in my environment.

It turned out that the issue was not Hyper Threading related, but a Bios misconfiguration instead. This is an excerpt of his blog post:

In the process of asking the question and researching it ourselves, we discovered the answer. These Dell servers were inexplicably shipped with BIOS settings that …

  • did not allow the host operating system to control the CPU power settings
  • did not set the machine to high performance mode
  • did not scale CPU speed under load properly

… kind of the worst of all worlds. But Kyle quickly flipped a few BIOS settings so that the machine was set to “hyperspeed mode”, and performance suddenly got a lot better. How much better?

A conclusion of this experience, check for Bios Configurations. Dell needs to tell their customers which settings can be beneficial for certain applications, like SQL Server.

SQL Server 2008 R2 and Nehalem Processors

I want to share a note about our latest experiences with SQL Server 2008 R2 EE X64 and Nehalem Processors. We have an active/active SQL Server cluster solution running on Two Dell R710 machines and Equallogic Storage Solution using iSCSI. Each Server has Two Intel X5550 processors, 64 GB of RAM and is running under Windows Server 2008 R2 EE X64.

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