[DUG] XP, hyperthreading and speed

[Kyley Harris]

Its been proven long ago that Hyperthreading slows down a delphi multi
threaded app.. Any Server app I have on a hyperthreaded machine can go 10
times faster if I force it to use only 1 cpu from the task manager.
something to do with Context switching in the app.. I don't know how this
would be under the new dual cores.. that was P4 architecture.

On 11/5/07, Rohit Gupta <rohit at cfl.co.nz> wrote:
>
>  I know I wont be believed, I can scarcely believe it myself.  Under some
> circumstances the display update for delphi apps is very slow.  the
> difference in speed we are talking about is 3 seconds and 23 seconds.
>
> When it is slow, all delphi apps are slow.  When it is fast, all delphi
> apps are fast.
>
> The only correlation I have found is that when the screen update code is
> running (painting 300  editboxes) if the load is balanced between the two
> cpus, the apps run slow.  If the load is on one side or the other, then the
> apps are fast.  While even one Delphi app is in memory, the speed remains
> consistent.  To switch, one must close all Delphi apps and wait a few
> seconds before launching them again.
>
> Is someone brave enough to postulate a theory ?
>
> --
>  *Rohit Gupta*
> * B.E. Elec.   M.E.   Mem IEEE    Associate IEE*
> *Technical Manager*
> *Computer Fanatics Limited*
> **
> *Tel*     +64 9 4892280
> *Fax*    +64 9 4892290
> *Email  *rohit at cfl.co.nz**
> *Web    *www.cfl.co.nz
>
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-- 
Kyley Harris
Harris Software
+64-21-671-821
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