Logical Processors - should be ENABLED or DISABLED in BIOS?


Supreme [H]ardness
Apr 9, 2002
Hey guys,

Just a quick question. We have a Dell PowerEdge R720 with an Intel E5-2620 @ 2.00 Ghz CPU. The server motherboard can handle 2 physical processors, but we only have one.

In the Task Manager, it was showing 12 logical processors. Now, after talking to Dell support, I went to BIOS and selected DISABLE under LOGICAL PROCESSORS. Apparently, I was told that this would be a performance boost, along with DISABLING the following under System Profile Settings:

Turbo Boost - was enabled, I disabled it
C1E - was enabled, I disabled it
C States - was enabled, I disabled it

So now, in Task Manager, I only see 6 processors.

So my question is - was this a good improvement? What did it do for me?

Any help will be greatly appreciated :D
The logical processors are hyper-threading cores I believe. Typically for Intel CPUs and that CPU in particular, it shouldn't negatively impact performance to have them enabled, therefore you shouldn't gain performance by disabling them, for most workloads. Turbo Boost enables the CPU to run a core or several cores at a higher clock speed when power/thermal conditions permit. Again, this should only gain you performance by having it enabled. The C-States are for low-power management when the CPU is idle and help save power/heat output by reducing the power that the CPU uses when idle. Clock speed typically drops accordingly as well.

Are you sure you spoke to Dell and this was their advice? Is there some specific workload that you are running that necessitated this? Am I just feeding the trolls? :confused:
Goddamn I really hope you're just trolling.

He isn't. I work with Dell R720's at work and you want "Logical Processors" to be enabled. Turbo Boost is up to you but if you leave it off you are throwing away potentially free performance. I'd only do this if you are really concerned about ensuring the CPU TDP stays as low as possible. This isn't normally a concern for smaller environments but in larger ones it may be a reasonable and desirable goal. C1E is again something you want enabled. With this disabled your running the CPU at full speed when it isn't necessary.