What exactly is a double bios graphics card and how would you use it?

[xYowie]

Can someone explain to me exactly how to use a double bios feature on a graphics card and why its useful? im looking at the 1080 ftw which has double bios that they say is better for overclocking.

 

[bystander]

They have a physical switch on them. They often have a stock settings bios and one with some built in OCing. AMD had one which had a fan profile difference, where one bios was quieter, but hotter, while the other was louder but cooler.

It can be nice to have a backup BIOS when you flash your card, in case something goes wrong, you always have a backup BIOS that works.