Unable to select Nvidia Graphics Card

I decided to download High Sierra on my computer but when I select my graphics card and restart my computer it doesn’t switch. I downloaded the right driver but it won’t switch. Every time I boot it switches. Flags tried USBBuxFix=Yes, nvda_drv=1 Specs: CPU - AMD FX8320E Motherboard - Gigabyte GA-78LMT-USB3 1TB of storage Ram - 16GB HyperX

Also side note I can’t get clover to load as the boot loader I have to use the USB install stick. Please help