Since I upgraded to 4.0 I've noticed a pause while printing through USB that didn't happen before on the previous version.
I have a Prusa Original I3 MK2 using Marlin software.
This does not happen in other software. I do hope there is a fix for this.
I have done everything I can possibly think of. Adjust window 10 power settings to basically do nothing but stay on. Updated drivers. Turned off verbose updates. Tried both USB 2.0 and 3.0 ports. New cables all 1 meter. I bought into this after 4.0 release. It is rather annoying and creates nice ugly blobs from the pauses. Sometimes I am forced to print from USB when I need to do filament changes. So saying print from the card if not a choice.
I'm having the same problem with version 4.0 on multiple machines at my school. Still waiting for resolution from tech support. They've been VERY quiet about this. Going back to 3.1.1 resolves this in every case.