32 or 64 bit, a question that seems as common as coffee or tea at the moment. It is a question that will fade away like a favourite old computer, eventually 64bit will be the dominant standard for both CPU’s and Operating Systems, 32bit will disappear. The progression of technology rolls on, stopping at all stations, are you ready for 128bit computing. Whenever possible the answer to the current bit question should be 64bit, it is the new standard for home computers.
Within every computer there is a single chip that runs everything, this chip is called the CPU or Central Processing Unit. Within that chip are a series of data pathways that shuffle data around to the different parts of the CPU. The memory spaces at the end of these pathways, the parking spaces for the data and the working memory within a CPU can be called the Registers – registers and caches technically –, but lets just call them all registers for now.
The bitness – 32 or 64 – of a computer system relates to the width of a chips registers and the buses that join them – think of them as highways through the chip -. The bitness of these parking spaces actually dictates the width of the pathways. There are a number of other internal changes to the chip designed to take advantage of the wider nature of 64bit, new commands and changes to the chips internal command set, this is all documented in the X86-64 documentation.
At the moment computer memory is also 64bit, but this is purely coincidental. 64bit memory is similar in that it also relates to the width of the memory pathways but the pathways lead to the memory controller not the CPU. Each 64bit bus on the memory controller is called a channel with some memory controllers having upto 4 channels, 2 and 3 channels are the most common. This structure is designed purely to shift as much data as possible and keep the CPU fed with data.
Just to confuse the whole situation other standards also use bits to define them. In audio the bits are used to describe the resolution of the sounds, pictures use it to define the colour depth and with video it’s the bit rate of the compression. As always more bits are better. All of these systems use the accumulation of bits to build a number. In audio 24bits is enough to reproduce sound, pictures use 32bits to hold the colour information of each pixel, giving enough space to store a number ranging from 1 to 4billion or up to 4 billion colours. All of these bit uses have no effect on the main bit question 64bit Windows or not. In the early days of video cards there were a number of transitions through the bits, like a car going through the gears. 8bit text only video cards gave way to high colour 16bit graphics – 65536 colours – video cards that eventually had to step aside for the 24bit photorealistic 2D video cards, Matrox was the leader in this style of card. The integration of 3D graphics was also part of this evolution with 3D specific chips from 3Dfx and Nvidia being added to the early 24bit graphics cards to make the forefathers to todays video cards.
In the computer industry there have been many transitions with the shift to 64bits just being the latest. This is the third bitness transition in the home computer world so far, the original shift from 8bit to 16bit involved new computers, software, the works. Computers like the Commodore 64, Apple IIe were both 8 bit machines and there was no way to easily retro-fit the parts needed to make these systems 16bit. 16bit computing introduced the Amiga, Atari ST, Mac Classics and IBM PC XT. Apple did make a bridge card for the Apple IIe, it allowed you to run the new Mac OS on an Apple II. The fact it was actually a complete Mac Classic on a card made it expensive and a tad ridiculous, it was cheaper to simply buy a complete Mac Classic.
The downsides to 64bit, the minimum bits for a command are 64 now instead of 32 bits so apps take up more space per command. This adds up and does lead to using a lot more space to install an application. When 64bit operating systems like Windows XP 64 first arrived on the desktop there were a lot of issues with the driver software. Every piece of hardware in your computer has a little bit of software that the OS uses to run the hardware. This software really needs to be re-written for 64bit. In the early days of 64bit Operating Systems lack of driver software lead to the sort of situation where you had to be careful what gadgets to buy and connect, always having to check if the drivers are available for that gadget. This is definitely not the case with Windows 7 64bit, all common hardware and most exotic gear now has drivers and all new hardware is released with 64bit drivers as standard.
For 64bit to become established everyone must switch to 64bit hardware, operating system and application software. Thankfully there is backwards compatibility built into all modern operating systems that will allow us to keep using our old software until we have a chance to get a newer 64bit version. Both of the Intel and AMD 64bit CPU families have 32bit mode that allows them to run 32bit software at full speed. Windows and Mac OS X can use this ability to make sure older 32bit software all runs properly and at speed. This is not old school grunt emulation but hardware based emulation. To fully take advantage of 64bit CPU’s we need to be using a 64bit Operating System, 64bit driver software and 64bit application software. As far as OS’s go Mac OS X is now fully 64bit, Linux has been 64bit for years and with the release of Windows 7 over half of new Windows machines are 64bit, so we can consider 64bit dominant when it comes to operating systems. The acceptance of Windows 7 has helped driver software shift to the new platform and as mentioned above all common gadgets and most exotic hardware now have 64bit drivers available. Application software is being converted from the top down with the most powerful app’s converted first, the reasoning being these are the applications that will see the most advantage. Adobe, Macromedia and Microsoft have converted all of their biggest applications to 64bit, so while this part of the transition may seem slow at times there are no stumbling blocks at the moment. If you are upgrading operating systems or buying a new computer pay attention to its bitness, 32bit or 64bit. The 64bit OS’s are becoming dominant so buying a 32bit operating system will only lead to an early upgrade in the near future. All CPU’s on the market are now 64bit, with only the current Atom CPU still being 32bit only.
The most talked about advantage of using a 64bit operating system is the ability to make use of more than 4GB of Ram in your computer. While 4GB may sound like a lot of memory it is the minimum amount of memory for new computers. A machine that needs to do any heavy-duty lifting like Photoshop or video editing will need to look at 8GB of ram and a 64bit operating system. A system like that would also show the other advantages of 64bit operating systems. By its nature of being a super wide highway a 64bit CPU shifts large amounts of data from its memory into its registers to do work. Granted even a 32bit operating system will work faster in that way on a 64bit chip, a 64bit Operating System is better designed to work with these wider highways. Part of the work to make an operating system 64bit is fine tuning the various parts of the OS that control memory usage and multi tasking. For windows 7 Microsoft re-wrote these sections of the OS. Upgrading Mac OS X wasn’t much of an issue as it was based on NextOS which already had the most advanced memory and multi tasking.
Windows 64bit or Windows 32bit is the most common bit decision at the moment. It is actually a no brainer question now, unless your buying a netbook – any Atom CPU computer – then buy Windows 64bit. Windows 7 64bit will run most 32bit applications you may have, there is very little downside and all upside with going 64bit at the moment. A year ago the equation was a little different, the amount of 64bit drivers and other software was still a little behind 32bit. With the uptake of Windows 7 – 25% of Microsoft’s market share in Dec 2010 – this equation is changing, 65% of new windows machines have the 64bit OS and a large chunk of the remaining being Atom based CPU sales.