so as far as I know i have to upgrade the bios so i can use a 9th gen processors on any z370 motherboard. Can i upgrade the bios with the 9th gen CPU installed ?or is the motherboard not gonna post ?
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guess you didn't look far enough. You could try to get the bios update on a flash and run it if you can get into bios. But you could just ask the seller to update it for you, depends on your country and seller. We have sellers that even test and show you the parts working.
Either that or just get the z390 and get over the drama.
Honestly if you had asked this a month ago I could've told you my bios version that came with my Aorus z370 tho that may differ. Check the manufacturer's page and see the bios version they ship it with (exact same version and revision)