I had one of those early Macs. If you check the official Lion support page from Apple, you will see that it requires an Intel "Core 2 Duo", that's the model th

I had one of those early Macs. If you check the official Lion support page from Apple, you will see that it requires an Intel "Core 2 Duo", that's the model that came after the Intel "Core Duo" (without a 2 in between) that shipped with the early Intel macs. Snow Leopard (the version before Lion) does support the "Core Duo" processors, but they can only run 32-bit apps there, because the very first Intel Macs from Jan 2006 used 32-bit Intel CPUs. The ones that replaced them in September 2006 had x86_64 CPUs. Apple killed support for PowerPC and 32-bit x86 at the same time with Lion.