Re: [ARSCLIST] Hyperthreading (was Software for Mac)

["Richard L. Hess" <arclists@xxxxxxxxxxxxxxx>]

At 11:48 PM 2008-10-17, carlstephen koto wrote:

> Thanks Steven, that's why I asked Richard about the hyperthreading
> before. I use a quad cored Mac (each processor is 2.6G) and when I'm
> processing audio, I open a widget that displays processor usage. When
> I run my restoration software (iZotope Rx) or any other intensive
> editing processes, only one of the four processors is doing 90% (just
> a visual estimate) of the work. If the one processor is "limiting
> out" a second processor will momentarily run up to about 50%.The
> other three are barely working (running the display and operating
> system?).  As a result, my software runs just a little faster than it
> would on a single processor.

Hello, Steve,

That was what I saw in the hyperthreading model as well under 
Windows. Alas, in hyperthreading, it appears that half the CPU cycles 
are allocated to each thread (as opposed to the multi-core 
processors), therefore in hyperthreading, I was losing performance 
with this function activated.

Your report on what the Mac does and what I've seen hyperthreading do 
under Windows are why I've been staying away from multi-core CPUs 
which have a big cost with little benefit IN THIS APPLICATION. In 
fact, I might suggest that other than efficiencies in fewer CPU clock 
cycles per instruction in the latest processors, that the typical 
mid-2.5 GHz multi-core processor may not offer any improvement over a 
3 GHz single core unit.

It would be interesting to see further data points on this.

Cheers,

Richard

Richard L. Hess                   email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
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