To hyper-thread or not to hyper-thread

[Aaron Konstam]

On Mon, 2009-12-07 at 16:18 +0100, Joerg Bergmann wrote: 
> Am Montag, den 07.12.2009, 09:02 -0600 schrieb Aaron Konstam:
> > I acquired another computer recently that has a Pentium(R) 4  D CPU Dual
> > core that is capable of hyper-threading.
> > 
> > I was not satisfied with its performance so I looked carefully at its
> > configuration and found that hyper-threading was disabled. A little more
> > looking and I noticed that hyper-threading was disabled in the BIOS and
> > could not be turned on. So what are my options if I want to enable
> > hyper-threading and is it worth it?
> > 
> > One option I assume is to find another BIOS. Are there other options or
> > if it is disabled in the BIOS it is disabled?
> > 
> > Another question is how much boost in performance should I expect from
> > the dual core SMB functionality of the CPU?
> > --
> 
> The problem of the Pentium 4 D: It is not really a dual core one.
> Hyper-Threading means: There is one core with two execution paths, which
> means some of the common CPU features, but not all, are present twice.
> As I remember: Under some circumstances, there were some percent
> performance boost. But mostly there was more a performace loss if one
> enables hyperthreading on a P4. That may be the reason for having 
> disabled the hyperthreading in the BIOS. Things may have changed with
> more up-to-date INTEL hyperthreading CPUs...
> 
> Joerg
> 
Thanks that makes sense. For your information the current Intel XEON
processors use hyperthreading productively. However, Intel lists this
CPU as one where hyper-threading is available but as you say it may not
be productive.
--
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He who laughs last -- missed the punch line.
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Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam at sbcglobal.net