Clicks, pops and distortion when using the midi editor

Hi, I have a really low end computer, with bad specs, but it works for a lot. I often freeze tracks to lower cpu usage because on some projects it can get up to 80%. But it doesn't matter how many tracks I freeze and what I do because when I use the midi editor to play back or add notes the sound has distortion, clicks, pops and I don't know what else. But it is only when I use the midi editor, so for example when I playback my song while having the midi editor open, it is distorted but as soon as I close it, it is perfect with no noise. I have checked and the cpu usage is not high and probably does not exceed 40%. The midi that I edit is my drum machine(MT power drum kit 2). What is the problem?

Enable Allow on tracks with opened MIDI editors in Preferences > Audio > Buffering under FX processing/multiprocessing settings > Anticipative processing. Anticipative processing renders audio a bit ahead of time. Processing for the track and its routing has to be done in real-time otherwise. Your CPU probably cannot deliver a full audio buffer in time hence the audible glitches. You can see this in View > Performance Meter: the RT CPU and RT longest-block metrics.

Thanks cfillion, I have had the same problem for ages and it has been driving me bonkers. Works perfectly now.