Apple switched to Intel with first generation Intel Core Solo/Duo which were 32 bit CPUs in mid 2006. Then later that year they released "late 2006" models usin

Apple switched to Intel with first generation Intel Core Solo/Duo which were 32 bit CPUs in mid 2006. Then later that year they released "late 2006" models using Core 2 CPUs which were 64 bit. However, they only has support for 32-bit EFI so they could not boot 64-bit OS. https://everymac.com/mac-answers/snow-leopard-mac-os-x-faq/mac-os-x-snow-leopard-64-bit-macs-64-bit-efi-boot-in-64-bit-mode.html https://everymac.com/mac-answers/snow-leopard-mac-os-x-faq/m...