Previous mainstream personal computers were 32bit machines. This means they are capable of executing 32 binary instructions per clock cycle. Never mind if you don't know what that means, it's not that important. The important thing is that 64bit processors are capable of performing 64 binary instructions per clock cycle and that means... they're faster.
The good news is that both of these new processors will support all of your old 32bit applications and software... BUT you won't get any benefit from the new processor unless you upgrade to software built specifically for this 64bit platform. Most 64bit computers available from your retailer will come with Windows XP 64 ... which is Microsoft's operating system for the new processors.
So this is the present... but what about the future?
According to "Moore's Law", the number of transistors on a piece of silicon will double every 18 months. He stated this nearly 40 years ago and, to date, he has been proven correct. This means that eventually the transistor's will become so tiny and the space between them so negligable that the transactions between them will become subject to quantum law and they simply won't work.
The solution for this problem, claims processor giant INTEL, lies in their new "Multi-Core" technology. This involves placing two processors in parallel in a single chip and using multi-threading technology to split the load between them. This means lower power requirements, less heat and more speed... provided the software you use supports it.
Multi-Core technology is only a stopgap of course. We must rely on the legion of scientists worldwide who are making incredible advances every day in both Quantum Computing and Biological Computing to come up with a better way to make processors before our hunger for more and more speed becomes our downfall.
Third Rock Design