what are you using as the master MIDI clock? the DAW? if so, the 'inaccuracy' of the clock is almost definitely a product of OS prioritisation..
MIDI in computer operating systems is low priority... so other things wich are higher priority, such as audio, usb mouse and keyboard signals and internet, for example, cause interrupts and hence can disrupt MIDI processing, to the point that it can be noticeable...
things that you can do to get round this are - sync to audio - ie use an audio track/loop to sync from the DAW at 24ppqn... or find something that can be used as an external MIDI clock and sync everything to that, including your DAW...
otherwise, turning off wifi and bluetooth etc may help to some extent...
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities