By changing the blocksize using ASIO (via port audio) you can control the soundcard buffer, when using ASIO 

normally this needs to be set @ 256, depending on the hardware you can use 128 and 64.

Many times there are problems using ASIO with the default 64. 

If you install Asio4all you will see that the “buffer” is set by pd`s “blocksize”.

> Date: Tue, 5 Jul 2016 13:10:43 -0700
> From: msp@ucsd.edu
> To: porres@gmail.com
> CC: pd-list@lists.iem.at; mikkel@klokke.dk
> Subject: Re: [PD] Cannot change blocksize (Mac OS X)
>
> Windows. Ask them...)
>
> On Tue, Jul 05, 2016 at 05:08:52PM -0300, Alexandre Torres Porres wrote:
> > I see, and why is it needed? I mean, if this sets latency, which is also
> > set by ms in delay, why do you need this second one in windows? I'm not
> > sure if I get what it does, is it really the same as delay in ms?
> >
> > cheers
> >
> > 2016-07-05 17:05 GMT-03:00 Miller Puckette <msp@ucsd.edu>:
> >
> > > It seems to be only needed on windows systems - I've had to push it to
> > > 4096
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