Yep, that’s right. The 64 bit extensions to the x86 architecture were invented and first implemented by AMD. Intel were laggards to the 64 bit party because they were hoping to transition away from x86 architecture and move us towards IA64. IA64 already existed in the form of the Itanium and Intel was hoping to transition towards that. Despite being a far better and more efficient architecture, lacking the inherent design flaws of x86, it suffered through lack of compatibility and it never took off except in the commercial space. AMD effectively forced Intel’s hand by introducing the Sledgehammer, which was effectively a 64bit chip based on the x86 architecture. Hence the name AMD64.