What's the difference between a 16bit, 32bit, and 64bit processor?

Question

Will old software run on a newer processor?
Will new software run on an old prossesor

Answer 1

The main difference between a 64-bit processor and a 32-bit part is the width of the processor's internal registers which is (obviously) 64-bits instead of just 32-bits.

This means a 64-bit processor is capable of doing more work than a 32-bit part during the same period of time as it can handle bigger numbers or 'chunks of data' at the same time.
Of course the application(s) you're running must be optimized, i.e. they must be able to make use of those 'big' numbers in order to gain any kind of advantage from a 64-bit processor.

An additional advantage of a 64-bit processor would be the capability to natively handle a much bigger amount of system memory than a 32-bit part (4GB max).

Current AMD64 processors have a 40-bits memory address space as that is already sufficient to allow a single processor to handle 1 Terabyte (=1000GB) of memory.

Now, as far as the processor's external connection is concerned, i.e. the connection between the processor and the rest of the system, it is completely irrelevant in terms of raw processing power.

The external connection does, of course, have a significant effect on your system's overall performance, as the fastest processor is useless if you can't feed it with enough data from the outside.

As for your postulate that a 64-bit processor is 'fast' because it must also have a 64-bit external connection (or 'bus'), that assumption is completely incorrect.

A 64-bits-wide external connection was first introduced (in the PC world) with the 5th-generation of processors (Pentium I / AMD K5).

If you look at the width of an Athlon 64's external connection (its Hypertransport-Link), you will note that it has a total width of only 32-bits (16-bits each for the up- and downstream parts of the HT-link) and still, a modern Athlon 64 processor's HT-link can transfer about 15 times as much data per second as an AMD K5 or intel Petium I processor's 64-bits-wide FrontSide Bus (533MB/s vs. 8000MB/s).

And that's without adding the bandwidth of the connection between the processor and memory which is dedicated here (integrated memory controller) and not shared with the main external connection (= what is referred to as 'FSB' on older platforms)...that'd be another 6400MB/s.

New software will still run with the old processor. But older software with lower bit support might not run well with 64bit processor.

Answer 2

the necessary vast difference is how severe the gadget can count number. A 32bit pc can in effortless words count number to 2^32, or 4 Billion, therefore the reduce of four Gbytes for memory length on a 32bit OS. A sixty 4 bit pc can count number to 2^sixty 4, in fact an infinitely large huge style even with what between the poster's stated, sixty 4 bit OS's are many times quicker than are 32bit they're waiting to procedure archives in larger chunks are are more beneficial powerful in maximum activities. maximum all Intel and AMD processors that were for sale for the surprising 4 years were sixty 4 bit chips and so are waiting to run a 64bit OS. I merely upgraded all of my abode computers to 64bit abode windows 7 with spectaculalry sturdy consequences. I rather recoomend it. Astrobuf

Answer 3

http://en.wikipedia.org/wiki/16-bit
http://en.wikipedia.org/wiki/32-bit
http://en.wikipedia.org/wiki/64-bit

They are all ways in which processors process information. If you have a 32-bit processor, it is best to have a 32-bit Operating System, but you can run 16-bit if you have to although it will not be as good. The same goes with 64-bit, you can run 32 and MAYBE 16 bit software, but it is best to run 64-bit. You cannot run higher bit software on a lower bit processor.

Answer 4

The bus width of the processor, yes, and not necessarrily.