For each rotation of the mouse wheel:
Hive: HKEY_CURRENT_USER
Key:
Control Panel\DeskTop
Name: WheelScrollLines
Type: REG_SZ
Value: 0x0 –
0xFFFFFFFF
0 disables scrolling. A number up to the number of lines on the screen will
set scrolling to that number of lines. If set to a number larger than the number
of lines on the screen, the scroll will be to the next (previous) screen of
text. Experiment for yourself but a setting it to 0xA works for me.