I tested again and seems to be on every knob. It goes like this; i change a parameter, the "led ui" on the synth shows the param name and a value and it freezes

I tested again and seems to be on every knob. It goes like this; i change a parameter, the "led ui" on the synth shows the param name and a value and it freezes for some 40-50secs. During that time ui is totally unresponsive. After the freeze time the ui might come back, maybe burst a note or two, or might hang like that forever. My computer is an old core 2 quad, but i'm working on a webaudio project myself and by my estimation it should be able to handle your synth easy. Also, in case it helps. I've found some hard to debug webaudio issues, like osc hanging in forever and 'cpu leaks', but your issues seems more related to how the ui is updating the audio graph.