This is in part a response to a comment by Paul White (@SQL_Kiwi) to my previous post on the performance impact of enabling hyperthreading (HT) on OLTP queries, and in part due to my desire to capture a more complete set of test data for future investigation on this very topic. I’m posting below the results of re-running the same exact test as ...

My previous post focuses on the performance impact of enabling hyperthreading (HT) on a machine with four Intel Westmere-EX processors on reporting queries. Let’s turn our attention to OLTP queries. To oversimplify it, reporting queries are generally processed by scanning a large number of pages, whereas quick index seeks are the hallmark of OLTP ...

There are a lot of questions on hyperthreading, but not a lot of answers.  There is no shortage of opinions, but very few are based on significant first hand experience or solid test data. We know that the hyperthreading technology in the older generations of the Intel processors was not well received by the SQL Server community. ...

Common wisdom with previous generations of server hardware was that SQL Server might not benefit from hyperthreading or could be degraded at high CPU usage; does anyone have definitive data about Nehalem (non-EX) servers and SQL Server 2005 or 2008? Here are some ...