Has anyone ever done any database performance comparisons with hyper-threading enabled vs disabled? We are running ibm db2 and I'm curious if anyone has an recommendations for enabling hyper-threading or not. With hyper-threading enabled it makes it quite difficult to do capacity planning for cpu usage. For example. "With 8 physical cores represented as 16 "threads" on the OS and a cpu-bound workload, does that mean when your cpu usage hit's 50% you are actually running at 100%." What real benefits do I gain with leaving hyper-threading enabled on an intel server running DB2? Does hyper-threading help if you're workload is truly disk IO bound? If so, up to what percentage? These are the types of questions I'm trying to answer. Any thoughts?