MSI RX 480 bios modding causes unresponsiveness

[Copperhorse]

I have 5 msi rx 480's.
Cards - https://www.newegg.com/Product/Product.aspx?Item=N82E16814137039
Motherboard - https://www.amazon.com/gp/product/B019EYYNP0/ref=oh_aui_detailpage_o02_s02?ie=UTF8&psc=1

I am trying to mod them with ATIwinflash. When I copy the value of 1750 to 2000, I save it and restart the pc. Now the card that I modded is not seen in windows and it is the only card that spins at idle. Any idea what causes it? When I revert back to original bios it works fine. Please help me as I'd like to mod my cards for better performance.