Hyper-Threading question

Doh_boy

Part of the furniture
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I've got a load of (sorta) new dells at work and they all have intel processors with Hyper-threading. Thing is it's turned off in the bios. Is there any reason why I shouldn't turn it on?
 

Jonty

Fledgling Freddie
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Dec 22, 2003
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Hi Doh_boy

Providing both the CPU and motherboard both support hyperthreading, then there's no reason that immediately springs to mind why it shouldn't be safely turned on (don't take that as definitive, mind you :)).

You can read about Intel's Hyper-Threading technology, but essentially it allows a single physical processor to appear to the operating system as two logical processors. The operating system doesn't know the difference and feeds threads to each as if they were indeed separate physical processors. This can in turn lead to fairly obvious benefits in some situations.

You might want to contact the supplier before changing anything, just to see if there's any reason why HT is disabled by default on the systems.

Kind Regards
 

PR.

Fledgling Freddie
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Dec 22, 2003
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If they run Windows XP and you have admin rights I don't see a problem.

You need the admin rights as XP will need to install a 2nd CPU driver
 

Doh_boy

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PR. said:
If they run Windows XP and you have admin rights I don't see a problem.

You need the admin rights as XP will need to install a 2nd CPU driver
Cool, I'm the admin :D so I'll test a pc today. I may only use it if people complain about the speed of the pc. Save me going round changing them all. :)
 

Xavier

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Actually under XP you can't install a second driver to enable HT. If you read Intel's support pages you need to reinstall the OS as the operating system will have been installed with the wrong hardware abstraction layer (uniprocessor) and thus SMT support won't be available.

Dell however may well have provided the machines with HT enabled in windows by disabled in the BIOS because of the IT policy at your company. Some bespoke apps really don't like it yet, and rather than just code fixes some software vendors state it should be turned off in their support pages.

Of course, even if Dell did provide an SMT friendly install of XP, there's no guarantee that your company didn't just blitz some standard OS ghost onto them, thus undoing all the good work on their part ;)

Xav
 

Gurnox

One of Freddy's beloved
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Dec 28, 2003
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I read somewhere that turning HT on will actually slow certain apps down. According to the article, it's only really multi-thread aware stuff (Lightwave, for example) that will really make proper use of it. Which I suppose makes a certain amount of sense.

Not played around with it yet, so couldn't possibly comment from a personal point of view.

Good work by Dell? Surely you jest? ;) (Quality notebooks excepted).
 

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