some midi notes not playing

Please pardon such a newbie question.  Some of my midi notes seem to be randomly not heard -- I am using the default soft synth along with sometimes the SI ones, especially SI Bass Guitar.  I am completely new to soft synths.  I assumed I was having polyphony issues like in my old hardware sound modules -- although it was and is the case that the disappearing notes also work sometimes, sometimes most of the time.

So I have been going through moving notes that don't sound 1 tick back -- and this does seem to make them play more consistently.  But I was programming a midi song from scratch the other day and it was doing the same thing even though there were very few midi notes being played at all so I don't think its a question of too many notes being asked to play at once.
 
My next guess is maybe my PC -- the most basic of basic windows laptops running windows 10 -- just lacks the RAM or the horsepower, but I don't know if that is it or not.  Anybody got any ideas of what I should be looking at to try to fix these notes that play sometimes and sometimes they do not?  The critical ones seem to be kick drums and bass notes -- so I have been going through and moving them one tick off of zero and that seems to help but maybe it has just been a coincidence?
 
Thanks!

Check the size of the MIDI buffer in Sonar's advanced preferences. If it's less than 500ms try raising it to 500ms or even more.

That buffer tells Sonar how gar ahead of the now time to start preparing MIDI output, and if the buffer overflows you get missed notes. On some systems 250ms works fine, others require more and there doesn't seem any obvious reason why, they "just do".