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.