Due to the hardware architecture, the mouse lag is a result of the P2815Q requiring 100 ms to process video data. This cannot be changed with a firmware update. It would require a new architecture from the ground up which we will not do. If you have this complaint, your only recourse is to return the monitor for refund. Outside of the initial 30 days from the invoice date, it will take manager approval to get a refund. Using the Dell service tag number from the P2815Q, contact Dell Technical Support for your region. Explain that we do not have a fix for this complaint. The technician will need to escalate to their manager.