I have deployed 4 IBM HS21 Blades (2 at one client and 2 at another) with Intel Xeon 5140 and 5160 Processors (2.33GHz and 3.0GHz respectively) and all of the systems show that HyperThreading is supported, but not enabled when I look at Processor on the Configuration page in the VI Client. All of these systems are running VI3 Enterprise Edition 3.0.1 with all of the latest patches applied. I have the latest version of the BIOS installed as well.
I have checked through the BIOS on these systems and can find nowhere to enable or disable HyperThreading. Typically HyperThreading is under the Advanced Processor option in the BIOS on the IBM systems, but not on these HS21s. Has anyone else seen this behavior or found a fix/remedy?
I found the answer to my own question. The Intel Xeon 51xx line does not have Hyperthreading. The Xeon 50xx line does have Hyperthreading. Can't enable something that does not exist Weird that ESX says it is detected but not enabled.
Either way this was not a show stopper, just a curiousity.