Have you seen this thread
It's easy to measure input lag objectively with this stuff.
1. Enable Dual Mode. Blue will be Device1 and green will be Device2.
2. Move the 2 mice together, pressing
them together while collecting.
3. Open Plot and choose xVelocity. Maybe DPI-s weren't accurate so change it to make the speeds equal. You don't need to Collect again, just change DPI and press Plot again.
4. When the speeds of the 2 mice are equal, use the Input lag delay field.
IMPORTANT: one measurement is nothing. The result may vary, so make at least 5 measurements to get rid of errors.
Here's an example measuring Razer Mamba's input lag in wireless mode, compared to G100s, both at 500 Hz. Blue is G100s.