Topic by Michael H

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  • Michael H
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Topic: CPU frequency and performance index oddity

I've installed PTeq 3.5 on my Desktop computer and it's doing fine, with a performance index around 30-31 (how high does it go anyway?)

For live performance I'd like to install it eventually on one of my identical laptops- they're both single core 2.13Ghz Pentium M's, the only major difference is that the one I've had longer has 2GB of memory and more programs, the other has 1GB memory and is basically empty. Both run XP SP3, and both have the demo version of PTeq 3.5 installed. I'm using an Echo Indigo DJ soundcard and it's Asio drivers. Now the weird part.

One machine shows a CPU frequency of over 2000Mhz and a performance index around 12-13, which I suspect is normal. The other PC's CPU frequency (within Pianoteq) varies every time I start PTeq but hovers usually around 111Mhz to 190Mhz, with a perfomance index of 1 or 2. Yet when I go into msinfo32 and get processor info, the CPU is running steadily at 2127Mhz. After uninstalling and reinstalling PTeq it's still the same. As far as I know I've adjusted Windows power management settings properly.

I'd appreciate any suggestions.

Reply by skip

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Re: CPU frequency and performance index oddity

Michael,
I suspect that you actually have the processor in power saving mode.

Have a look at the output of the POWERCFG /Q command (from the command prompt), and see what the Processor Throttle lines say. It should say NONE.

Also, I've just put my processor into a constant downgraded mode, and msinfo32 still reports the full speed. So, msinfo32 cannot be used to check the operating frequency, it seems.   Instead, use the Intel Processor ID Utility: http://www.intel.com/support/processors/tools/piu/

Power management profile names can be misleading. For example, I have one called "Maximum Performance(Dell)". This profile actually uses dynamic speed switching!  So, I use "Always On" instead.

Intel Speedstep FAQ: http://www.bay-wolf.com/speedstep.htm

Greg.

Last edited by skip (27-11-2009 11:28)

Reply by Michael H

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Re: CPU frequency and performance index oddity

Thanks Greg,

What a great little app that Intel Processor ID Utility is! It did tell me however that my CPU is running at the correct frequency, but it's not being shown in Pianoteq. I did a bit more problem solving.

First of all, I had jumped the gun when I assumed that one PC was showing the correct CPU frequency on a regular basis- it too is all over the map. The problem only occurs with my Echo Indigo PCMCIA soundcard and not with the Asio4All driver and onboard sound. There is some form of digital noise coming through the internal speaker system even when the internal speakers are supposedly inactive and audio is being routed through the Echo card. Something's making me think it's similar to radio interference for some reason.

The computer is a Dell Latitude D610, known for pretty poor onboard sound quality. The Echo card, with an Ebtech ground loop eliminator (actually, a line level shifter) cleans up the outbound Echo audio very well, but I'm thinking maybe it's producing some kind of internal PC interference that prevents Pianoteq from measuring CPU frequency properly. Does this sound possible to you?

Again thanks for your help,
Michael

Reply by skip

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Re: CPU frequency and performance index oddity

Michael,
Very interesting.  I don't think "interference" could affect Pianoteq's frequency measuring. Maybe there is something else running on the PC which is consuming appreciable CPU cycles? If you monitor the system without Pianoteq running, what does the CPU Usage meter do?  I think it's over to Modarrt!

EDIT: Sorry, therei is one more thing - did you actually run POWERCFG /Q? That is important too. You have to make sure that THROTTLING is "NONE". It is possible that even though the CPU ID utility showed the correct freqiency at the time you ran it, that the frequency may still sometimes drop due to power management. 

Greg.

Last edited by skip (27-11-2009 21:45)

Reply by Michael H

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Re: CPU frequency and performance index oddity

Greg,

Well, in Task Manager, CPU usage is 0-4% without Pianoteq running, and using powercfg/q I just checked throttling, and both AC and DC are set to NONE.
The fact that frequency measuring is normal with Asio4All, but not with the Echo card definitely seems odd. Electromagnetic voodoo perhaps?

Michael

Reply by jcfelice88keys

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Re: CPU frequency and performance index oddity

Michael H wrote:

I've installed PTeq 3.5 on my Desktop computer and it's doing fine, with a performance index around 30-31 (how high does it go anyway?)

Hello Michael,

My two-year old MacPro Quad-core 2.66 running Pianoteq 3.5 on Snow Leopard renders a performance index of 43 when the sample cache is set to 512 samples @ 44.1kHz and maximum polyphony set to 256 notes.  No attempt was made to maximize the performance index ... 43 was obtained when running my normal setup.

My wife clicked the screen capture mode as I played the keyboard at ~40-45  notes sounding simultaneously (using sustain pedal) in order to stress test the computer.

Likewise, I don't know whether 31, or 43, or ?? is high or low.  Perhaps a Pianoteq moderator might care to share information about the Performance Index scale.

Cheers,

Joe

Last edited by jcfelice88keys (28-11-2009 07:45)

Reply by Michael H

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Re: CPU frequency and performance index oddity

Hi Joe,

It sounds like you've got a good system there! Well, we do know that a higher number is better AFA the performance index. How high it goes, or just what represents excellent/good/fair/poor would be helpful to know, so perhaps someone will chime in.

Michael