In my past experience, I had noticed that the BOGOMIPS reported on (each of 
the) hyperthreading enabled CPUs was half that of the same CPU with 
hyperthreading turned off.  Which made me believe that the 2 CPUs were 
effectively half the speed of the single one.  (That is, if single is 2 
bogomips, then hyperthreaded it was 1 bogomips on each CPU).

 

Since I knew that Linux did a good job of true multitasking, I always turned it 
off (assuming that part of the impetus for the whole thing was that Windows did 
a TERRIBLE job of true multitasking (remember trying to do ANYTHING else while 
doing a floppy format? Yeah, I thought you did J) so that windows could tie up 
one of the ‘CPUs’ doing a floppy format (or whatever) and still look responsive 
to the GUI using the other ‘CPU’.

 

So, I have to ask a few questions:

 

1 – does that slow 1.2GHz (SLOW? 1.2G? Wow, how times have changed!) play back 
fine with hyperthreading turned off?

2 – if XBMC gives a 20% performance boost on a CPU that is running at half the 
speed, is that really a performance boost overall?  (I’m probably missing 
something…)

 

Just wondering J

 

Rusty

 

From: [email protected] 
[mailto:[email protected]] On Behalf Of Bryan O'Neal
Sent: Sunday, May 04, 2014 9:48 PM
To: Main PLUG discussion list
Subject: Re: hyperthreading....

 

Short answer is that it is a way each physical core gets presented to the OS as 
two logically cores. Through some well documented voodoo it increases 
paralization for some work loads. Available on many Pentium systems since the 
Pentium 4 but also requires comparable chipsets so some early systems had 
processors that supported it but still could not use it. Mostly I see it on 
Xoen systems
Some bios allow you to disable it. 

On May 4, 2014 9:35 PM, "Michael Havens" <[email protected]> wrote:

what is it and is it an option in a modern BIOS?

I ask because I got an interesting message on another list othat I participate 
in.

[quote]Even though an AGP card may not support vdpau acceleration, a p4 should 
be able to use the Nvidia driver to get some openGL 2D accelerated output for 
XBMC. You should also have hyperthreading turned on in the BIOS, so the system 
will see two CPU cores, as XMBC will take advantage of that for maybe a 20% 
performance boost. My netbook, with a slow 1.2 GHz hyperthreaded Intel Atom CPU 
and 945M graphics, is still able to play back 720p h.264 encoded movies 
smoothly on MX 14.


Steve (finishing up the packaging of XBMC 13.0, which coincidently was just 
released)[/quote]

:-)~MIKE~(-:


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