Just built my first pc 5600X on a gigabyte b550 motherboard. 6750XT OC. but when i went into bios to enable smart access memory i found that it would not boot. enabled 4g decoding, re-size bar, disabled csm. But when i attempted to save and exit bios my pc would not boot. only back into bios and had to re-enable csm. has anyone had this issue before? something i am doing wrong?