Vista - Mouse DPI and pointer speed at the Mouse Properties.

I have bought a new wireless mouse, which allows me to switch between
DPIs of 400,800 and 1600. There is no display on the mouse so I don't
know what the current DPI is, but apparently, when I switch between
those three DPI's the pointer speed changes. I guess it's 1600 DPI
when I get the fastest pointer speed. But what about the "pointer
speed" option at the Mouse Properties item in the Control Panal?

<400 DPI + faster pointer speed> and <1600 DPI + slower pointer speed>
seem to be give me the same result, plus I guess maybe setting 1600
DPI consumes more battery power. And what about the "Enhance pointer
precision" option?

I would like to know the optimal settings for my mouse. My hardwares
and configurations are:
an 60cm (24 inch) LCD monitor
resolution 1920 * 1200
a wireless mouse with adjustable DPI of 400, 800, and 1600.

Thanks.