CPU load questions...


    Sep 21 2020 | 2:19 pm
    So I am working on a patch which is hosting a variety of VST3 plugins, including one or two fairly intensive ones, so I'm intent on making sure the patch is as streamlined as possible.
    When I monitor the CPU of the patch - with all VSTs enabled - I note the following: The average cpu is 63.33% (jumping to 70% at times) One VST is marked orange by the CPU meter - using between 30 and 40 % of total CPU. The other 5 VSTs all list as just under 10%, with all other patch objects under 2% [ (10 * 5) + 30 = 80, so I am assuming these values refer to 80% of the 63% CPU? ] With all this as it stands I get significant cracks and pops indicative of someform of buffer overload.
    IO and Signal Vector sizes are both at 256. Overdrive and Interrupt are both on. Sampling rate is 44100.
    Furthermore - lowering the vector sizes increases clicks and pops (thats normal) but reduces the displayed CPU load? (thats weird) So I'm definitely missing something here!
    In a DAW I could run these VSTs with little problem, and whilst I'm aware that the object might have some overheads in MaxMSP, things still seem off to me.
    I am very confused about the relationship between the listed CPU usage and the problematic buffer overloads I get. I usually wouldnt be worried unless CPU was reaching the 80% mark, but I feel I'm misunderstanding what the numbers actually represent.
    If anyone could help me find a way to accurately monitor the performance of the patch, as to prevent the buffer overload clicks and pops, or just explain how the CPU value relates to the audio performance of Max, I'd greatly appreciate it.
    Many thanks, James P.s. I'm on a good Macbook - 10.14.5

    • Sep 21 2020 | 7:10 pm
      lowering the vectorsize should normally increase CPU use of MSP objects like vst~ (except for instruments, which dont have audio in, which makes them almost immune to the small vectorsize syndrome.) the % you see in the DSP window more or less shows you "percentage of what would currently be available for signal objects" - without other things happening in max and without other applications - someone correct if that is wrong.
    • Sep 22 2020 | 7:35 pm
      Ah okay so what I will do next is to try and use activity monitor to see how the CPU is faring.
      However if the CPU % isnt the best indicator for when the I/O buffer will overload, what is? If there is such a way to acheive this...
    • Sep 22 2020 | 9:11 pm
      Okay so here's something weird - By activating all objects in the patch to make the CPU % as high as possible - it peaks between 65 - 75 %. This includes the ocassional crackle and pop at 256 Vector Size.
      However, if I enter presentation mode to see all the buttons (live.text, live.gain etc) the CPU % doesnt change, but I get constant popping noises!
      Anyone know what's going on?
      Gonna reformat my patch using normal text buttons and not the "live." versions and see if that makes a difference maybe...?