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Topic: CPU usage (Read 5591 times) previous topic - next topic

CPU usage

I've noticed on my last couple of computers that playing files in NWC seems to use pretty much 100% of my CPU resources. It did this on my old Celeron 300, and it still does it on a P4-3.2GHz machine. Am I the only one that has this problem? I don't believe this is neccessary, as NWC certainly shouldn't be this CPU intensive. It seems as if something in the code is being allowed to loop as fast as possible where the frequency should be limited.

Re: CPU usage

Reply #1 –
Don't know if this applies to you, but it's a good guess:

I've read somewhere that certain recent microprocessors unexpectedly go into high-precision computation mode when numbers are close to zero. If your music has some silent passages, in which the output waveform is zero, then the microprocessor may be going nuts trying to distinguish numbers very close to zero.

This may be caused by the conversion of MIDI (or MIDI-like NWC) code to waveform by audio software residing in the CPU. It is not particular to NWC.

One solution is to set a minimum volume to play at any given time. The least non-zero MIDI code is above the threshold for invoking the high-precision mode.

I'm not super-knowledgeable on this. Maybe someone else on the forum knows more than I do (highly likely!).

Re: CPU usage

Reply #2 –
That's a creative guess, but I doubt it's the case. :)

Playback hammers the CPU regardless of the song content, midi-device, or the playback device. It's very equal-opportunity.

So all of you can honestly say that if you leave your task-manager on the "performance" tab, and play back a song, it doesn't jump to nearly 100% (or 50% on a hyperthreaded Intel CPU)? I've come to assume this was issue with NWC.

Re: CPU usage

Reply #3 –
Just out of curiosity I checked this out.  My computer has Windows 98 2nd edition operating system, Athlon XP2200+ processor and 512 MB RAM.
Playing a song with NWC version 1.75, I register consistent kernel processor usage of 100%.  Playing the midi file version of the same song with Windows Media Player, kernel processor usage is less than 10%.  (The midi file was produced using NWC and saved as Type 1 Midi File).
I think it is connected with the graphics display.  A year or two ago I had to upgrade my cheap 4 Mb RAM graphics card in a system that had an AMD K6-3D 500 MHz processor, because I was experiencing funny problems with Noteworthy Composer.
Go into Tools>Options>Editor, and uncheck the "Chase playing notes" option.  When I do this, processor usage drops to 50% - which is the same usage as I get when I simply have the Noteworthy score open, but not actually playing.

Re: CPU usage

Reply #4 –
Thanks Graham. That narrows it down.

I tested myself, and it does indeed seem that chasing the notes requires the computer's undivided attention. When that feature is turned off, my CPU usage hovers near 0% during playback. I would definitely consider this a bug in the way NWC displays the music.

Re: CPU usage

Reply #5 –
Interesting.  Same noted here.  100% really does seem like a lot just to chase notes!
Sincerely,
Francis Beaumier
Green Bay, WI

Re: CPU usage

Reply #6 –
The note chase feature has always used 100% of the unused CPU.  It doesn't prevent other apps from doing things on the system, but it does use every ounce of idle CPU time. This is being considered for improvement in version 2.

In an idle, non-playing state, NWC uses basically 0% of your CPU (although the clock in the lower right of the status bar updates every 10 seconds or so, so it uses the slightest bit of CPU for a microsecond).

Re: CPU usage

Reply #7 –
but many programs like MidiNotate, Smartscore and
Midisoft they use low CPU usage when following the
notes, also, you can avoid it by opening a dialog
that disables the main window (this does not
work in Cakewalk) but it works in many programs

Re: CPU usage

Reply #8 –
Could NoteWorthy please point me to the feature in the "What's New" section of the NWC 2.0 are of this website that addresses fixing this problem?  I looked and I don't see where anything is listed that addresses the excess CPU usage when chasing notes is turned on.  This, in my opinion, is a critical fix that needs to be put in place.  No other notation program I've ever used takes up 100% of the CPU when chasing notes.  Thank you.

Re: CPU usage

Reply #9 –
I can't locate where the improvement is noted at the moment, but I have NoteWorthy Composer 2, and I remember downloading the preview that first had this enhancement.  Don't worry it's fixed.
Sincerely,
Francis Beaumier
Green Bay, WI

Re: CPU usage

Reply #10 –
There are many low-level improvements in NWC2 that don't necessarily get listed in the list of features. This particular efficiency improvement also appears in the NWC2 Viewer.

Re: CPU usage

Reply #11 –
Thank you.

Re: CPU usage

Reply #12 –
*-[Reply 8 by Tom B. on 2004-12-02 23:09:25

...No other notation program I've ever used takes up 100% of the CPU when chasing notes. Thank you.]-*

->>some notation programs that use 100% CPU: Vivaldi, Octava, Encore, Finale, Cakewalk, WinJammer
 

Re: CPU usage

Reply #13 –
*-{[Reply 3 by Graham Harrison on 2004-07-09 17:29:16]

...I think it is connected with the graphics display}-*

->>I think it's a Modal/window class problem

1) if you click on the menu and don't close it, the CPU usage goes down, if you close the menu, the CPU usage goes up again

2) if you open a modal window (a window that disables the current active window), and not close that window, the CPU usage goes down, if you close that window, the CPU usage goes up again