- Foreground vs. Background: Foreground boost means that the application currently having focus will get more quantums than other applications, thus it will not be disturbed that much by background processes. Background means that all applications gets equal amount of CPU quantums.
- Short vs. Long (Win2k+): Short quantums means that applications can hold the CPU for a short time, thus giving smooth multitasking. Long quantums means that applications can hold the CPU for longer time, thus spending less time on process switching.
- Variable vs. Fixed (Win2k+): Variable quantums means that the foreground application can hold the CPU for a longer time. Fixed quantums means that the CPU time within a quantum is the same for all applications (Though some applications can get more quantums than others).
The above setting reflects this DWORD value in the registry:
For the WinNT4 there are the following values:
[HKEY_LOCAL_MACHINE \System \CurrentControlSet \Control \PriorityControl]
Win32PrioritySeparation = 0
- 0 - Equal priority for all applications
- 1 - Medium priority to foreground application
- 2 - High priority to foreground application
More Info MS KB232271
|6-5 Bit||4-3 Bit||2-1 Bit||Result|
|10 (32)||Short Quantum|
|01 (16)||Long Quantum|
|00 (0)||Default (Prof.=Short, Srv.=Long)|
|10 (8)||Fixed Quantum for all|
|01 (4)||Variable Quantum for foreground|
|00 (0)||Default (Prof.=Variable, Srv.=Fixed)|
|10 (2)||High foreground boost/priority (3 times higher)|
|01 (1)||Medium foreground boost/priority (2 times higher)|
|00 (0)||No foreground boost/priority|
- Optimize Performance for Applications: 32 + 4 + 2 = 38 and gives Short Quantum, Variable Quantum for foreground, High foreground boost.
- Optimize Performance for Background Services: 16 + 8 + 0 = 24 and gives Long Quantum, Fixed Quantum, No foreground boots.
More Info MS Technet
Related Specify base priority when launching programs