32-bit vs 64-bit. What’s the difference?
In short, a 32-bit and 64-bit computer are different in architecture. The main difference lie in the length of data supported by each architecture. A 32-bit machine can only understand data that is 32-bit long. Anything more than that would not be able to read by the machine. Similarly, a 64-bit machine can read data up to 64 bit long. Even though 64 is twice of 32, a 64-bit data can hold much more than double the information of a 32-bit data. This also explains why a 64-bit machine can process and run faster and effectively than a 32-bit machine.
Another difference between 32-bit and 64-bit machine is the amount of memory RAM each can support. For a 32-bit machine, the maximum it can support is only 4GB, whereas for a 64-bit machine, there is theoretically no memory limit cap (or up to 17.2 BILLION gigabytes of system memory). However, most OSes limit to only 16GB (or 32GB) of RAM, which is considered very powerful for today’s desktop computing standard.
What is AMD64?
Instead of using 32-bit and 64-bit, people give them names. A 32-bit architecture is often referred to as i386 or x86 while a 64-bit architecture is widely known as any of the following: AMD64/EM64T/x86-64/x64, depending on the products and the manufacturers. Why AMD64, you might ask? According to Wikipedia, AMD was the first to come up with the specification of a 64-bit processor. They initially named it x86-64, but later renamed it to AMD64 when they released their first 64-bit processor: AMD-K8 series. Ever since then, AMD64 has become the term for 64-bit processor.
Intel (a competitor of AMD) obviously won’t use AMD64 name for its 64-bit CPU, that why they came up with EM64T, and later renamed it to Intel 64. In some Intel mainboard, during the BIOS bootup, you still can see the word “EM64T” appears in your monitor. In short, in today technology, AMD64 is now referring to the 64-bit architecture and is not tied with the AMD CPU.
Does AMD64 Ubuntu only works with AMD processor?
Back to the Ubuntu ISO download issue, if you are using a 32-bit computer, you will download the i386 version. If you are using a 64-bit computer, you will download the amd64 version, regardless what brand of CPU you are using. If you are wondering, a 64-bit computer can run the i386 (32-bit) version of Ubuntu as well. It is just that you are not utilizing your computer to the maximum. Lastly, don’t bother to run AMD64 Ubuntu on your 32-bit computer. Your system might crash.
Can I run 32-bit applications on 64-bit Ubuntu, and vice-versa?
In usual cases, you can run 32-bit applications on 64-bit Ubuntu, but you won’t be fully utilizing your system. However, the vice versa is not true. You won’t be able to run 64-bit applications on a 32-bit machine (just imagine, you can place a small container into a big container, but you can’t do that the other way round). When installing applications in Synaptic, you might notice that some software comes with the 32-bit and 64 bit version (only shows up when you are using the 64-bit Ubuntu). You can just pick the one you want. Additionally, not all 32-bit applications will work in 64-bit machine, particularly for applications that require access to system hardware settings.
