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After Upgrading from ESX Server 2.5.x to ESX Server 3.0.1, CPU Hyperthreading Might Appear to Become Disabled (8451742)
Why does CPU hyperthreading change from Enabled to Disabled when I upgrade my ESX Server 2.5.x to ESX Server 3.0.1?
After upgrading ESX Server from 2.5.x to 3.0.1, VI Client displays the CPU hyperthreading state as disabled even though it was enabled prior to the upgrade. This is a display problem rather than an actual state change—the underlying configuration retains the correct CPU hyperthreading state.
This issue is fixed in VMware ESX Server 3.0.2 and all higher versions.
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