Reducing CPU

What OS/device are you using? I'm not as familiar with Mac OSX, but for me using Windows the biggest difference for me was using an ASIO driver (such as asio4all) instead of built in audio. Often times audio interfaces and possibly some sound cards will have ASIO drivers which helps with all of the audio processing.

However, Pianoteq is a bit more complicated than that. There's a ton of calculations going on inside of Pianoteq (no samples, all modeling) which is why it is very CPU intensive. So while it is good to have a dedicated audio processor (such as a sound card or an audio interface) to handle the audio itself, that's only a portion of load that Pianoteq generates.

Reducing the sample rate helps, of course (a higher sample rate helps with high frequency generation and lower latency at the cost of more processing power).

Reducing polyphony is another good way to to keep the CPU down, as it limits the number of simultaneous voices (though Pianoteq is a little more complicated than that, but it still reduces the computations because there's less to compute when you have a limit).

I would say effects are pretty minimal to the CPU activity. The new convolution reverb will be the most CPU intensive, but again is pretty minimal compared to the physical modeling.

Increasing the buffer size is another good way to reduce the CPU, but the effects aren't as drastic to the CPU compared to how much latency that's added (the time it takes between pressing a key to hearing a sound).

There's one more setting you should take a look at that will be most beneficial to you. Go under OPTIONS > PERF and you will see a setting called INTERNAL SAMPLE RATE. This changes the sample rate of Pianoteq's engine. This will have the most dramatic effect in CPU. The downside is that decreasing the internal sample rate will darken the sound (because it takes a higher sample rate in order to accurately generate higher frequencies, see the Nyquist-Shannon sampling theorem). OPTIONS > PERF is also where you should be looking to see your CPU usage in real time.

All of this really depends on your system, and more importantly, how much you care about the quality. All of these settings have pros and cons which you're going to have to weigh.

The first thing I reduce is the sample rate. Often times I go with 48k as I feel it has the best compromise with quality and processing load. Next is reducing the buffer until it's within a range that latency isn't an issue anymore and the audio doesn't crackle an pop with too little of a buffer. After that I'll start playing with the internal sample rate until it bothers me (getting too dull). If at this point after I play something intense with a lot of chords and sustains and the audio still drops out, that's when I'll reduce the polyphony. There might also be a bit of tweaking here and there as all of these settings affect each other (buffer is directly based on the sample rate, internal sample rate is directly based on buffer and sample rate, etc).

Hope this helps! I often have to worry about all of this on my Surface 3 as it isn't very CPU powerful at all (but I LOVE the portability!).

Hi music yes,

You shouldn't have to degrade Pianoteq to 16 notes @ 11 KHz... Assuming that you don't have a very old computer/laptop, I think that you should inspect your system and find what is eating the processing power of your rig. If you need help, please gives us more details about your system.

You did not answer violincell... about what OS you're using so I assume it's some recent version of Windows. If you haven't done so yet install the ASIO driver for your sound card.
You shouldn't have to go to below 44.1kHz and 32+ polyphony unless you're using an old machine.