The colours settings in the display control panel (Win XP) was changed from 24-bit to 16-bit, this reduced
CPU load. But in Windows 2000 the colours are set to 32-bit and the CPU load is less than 2%, and in
Windows 98 the colours are also set to 32-bit and the CPU load is less than 10%. Clearly Windows XP is
trying to display the scope graphics at full colour specified in the display control panel.