I have a timer with interval of 1ms
No. you have a timer set for an interval of 1ms. The chances that it's actually firing at 1ms intervals is absolutely zero. Microsoft recommends a minimum interval of 35ms. most people 50ms and me 100ms. At best you'll get inconsistent performance, at worst you'll crash the event queue. Either way it's really not worth it. If you really need something to happen 1000 times a second (and that's extremely unlikely) then you should use one of the other VB timer classes.