What do you mean exactly? If you just want them to clock the same speed just link their overclocks in whatever overclocking software you use.
If you want every single bios setting to be the exact same for each card, then you will have to mod each one separately and change the settings one by one for both cards.
I suggest you remove the windforce x3, then modify the G1 bios and screenshot each page, flash it, and make sure it all works
then; uninstall the G1, reinstall the windforce, and use the screenshots to change the settings on that card's bios, flash it, make sure it works, then reinstall the G1.
I used this guide(very comprehensive)
a few days ago.Edited by TheShamen - 5/31/16 at 8:54pm