The higher priority does result in the kernel dispatcher giving more preference to the threads of the process in question. These user mode threads always end up getting preempted by higher IRQL kernel threads due to regular interrupts.
How do I change CPU priority?
Setting CPU Priority Press the “Ctrl,” “Shift” and “Esc” keys on your keyboard simultaneously to open the Task Manager. Click the “Processes” tab, right-click the program you want to change the CPU priority on. Hover your cursor over “Set Priority” and select a Priority setting.
What happens when you set priority to high?
Giving a process a higher priority won’t make it go faster. Your programs will never use more CPU time than they need (or more than 100% obviously). It just means that if you have two processes that both want CPU time, the one with a higher priority will get it.