Time in int will not change as that is dependant on the particular computer, changing the Kernel however changes the interrupt time for example
25KHz = 1 second/25,000=40uS
45KHz = 1 second/45,000=22uS
100KHz = 1 second/100,000=10uS
So as you can see the higher the kernel the more time, as a % of the interrupt, the driver will be taking up and thus the less time for the rest of the computers functions which includes Machs normal running and everything else windows is doing. That is why on some computers you are more prone to have lockups the higher the kernel you have. On my computer here at home the Time in Int is 2.5 so even at 100KHz my computer is only 25% a pulsing engine and 75% is left for other computer tasks.
Did changing to 45KHz help any?
Hood