I had a chance to run both filemon and regmon while hitting the dpi setting keys.
regmon seemed to provide more information. When switching to my fast dpi setting (2000 dpi), I get something like this
Code:
KHALMNPR.exe:1612 SetValue HKLM\System\CurrentControlSet\Enum\HID\ ... \Device Parameters\DpiIndex SUCCESS 0x2
KHALMNPR.exe:1612 SetValue HKLM\System\CurrentControlSet\Enum\HID\ ... \Device Parameters\DpiIndex SUCCESS 0x4
KHALMNPR.exe:1612 SetValue HKLM\System\CurrentControlSet\Enum\HID\ ... \Device Parameters\DpiIndex SUCCESS 0x4
And when I switch to my second dpi setting (1250 dpi) I get this
Code:
KHALMNPR.exe:1612 SetValue HKLM\System\CurrentControlSet\Enum\HID\ ... \Device Parameters\DpiIndex SUCCESS 0x4
KHALMNPR.exe:1612 SetValue HKLM\System\CurrentControlSet\Enum\HID\ ... \Device Parameters\DpiIndex SUCCESS 0x2
KHALMNPR.exe:1612 SetValue HKLM\System\CurrentControlSet\Enum\HID\ ... \Device Parameters\DpiIndex SUCCESS 0x2
So it seems like the difference lies in the final values, 0x4 for my first dpi setting and 0x2 for my second dpi setting.
I also ran a few tests where I only hit setting 1 while running regmon, and consistently got 0x4 as the SetValue. Same thing when only hitting setting 2, I consistently saw 0x2.
Any insight appreciated.