While I tried to learn more about the 64-bit processors, here is what I found out. There are two different sets of architectures present in the world today. The first is called the x64 architecture processors, which is based on the AMD64 and/or Extended Memory 64 Technology (EM64T) as the case of manufacturer may be. The other one is the Itanium processors, which is based on the Explicit Parallel Instruction Computing (EPIC). Nice terms right? Lets try to demystify these. Here is what I found about them.

The x64 platforms in 64-bit computing are offered by two main vendors – AMD and Intel.

AMD64 – AMD64 is AMD’s 64-bit platform that extends the industry-standard x86 instruction set architecture and defines a new class of computing. The AMD64 platform is the first designed to deliver full compatibility with existing x86 solutions and world-class 64-bit performance. To read more FAQs about the AMD64 technology go here. As of now, there are three ranges of processors that AMD offers which use the AMD64 technology
• AMD Opteron processor for servers and workstations
• AMD Athlon 64 processor for desktops and notebooks
• AMD Turion 64 mobile technology for notebooks

I do not want to go into the details of each type right now. In case you are interested AMD’s website might just be the best place for you to search more.

Extended Memory 64 Technology (EM64T) – The Extended Memory 64 Technology is Intel’s enhancement to its IA-32 architecture. The enhancement allows the processor to run newly written 64-bit code and access larger amounts of memory. These extensions do not run code written for the Intel Itanium processor. To read more FAQs about this technology, go here. As of now, there are these three ranges of processors that Intel offers which use the EM64T technology
• Intel Pentium D processor
• Intel Pentium processor Extreme Edition
• Intel Xeon processor

Interestingly enough, while searching, I found a site which states that Intel has commented that EM64T and AMD64 are the same, practically; apart from the differences – well I found this funny. Is everything not the same except for the differences??? :) :) Here is the comment that I got from the site "Even though the hardware micro-architecture for each company's processor is different, the operating system and software ported to one processor will likely run on the other processor due to the close similarity of the instruction set architectures".

The IA platform in 64-bit computing is offered by Intel.

Itanium-  The Itanium Processors moves users beyond proprietary Reduced Instruction Set Computer (RISC) architecture. This platform is based on the Explicitly Parallel Instruction Computing (EPIC) architecture. Now what is EPIC? EPIC is a 64-bit microprocessor instruction set, jointly defined and designed by Hewlett Packard and Intel. To read more about it, read here. As of now, Intel offers the Intel Itanium 2 Processor supporting this technology.

Well, hope this was a good summary and a nice set of links to read through!!

But wait a minute. I forgot to discuss what is x64. x64 is Microsoft's generic designation for the Advanced Micro Devices AMD64 and Intel EM64T 64-bit Instruction Set Extensions to the x86 architecture. It stands for Extended 64.

More later ... !