Original URL: http://www.theregister.co.uk/2011/03/15/64_bit/
The 64-bit question
Maybe the future of the desktop, but should you care yet?
Desktop Strategy There's no question: 64-bit computing is here to stay - and it seems set to be the future of computing. But is it an essential element of your next desktop refresh cycle? Chances are it will be.
The struggle to reach a stable 32-bit platform may have escaped you but it took many years before we were finally rid of slow 16-bitness. The main barrier to a major change of computer architecture is a lack of driver and hardware support. Until there's a critical mass of new hardware and software out there, it's unlikely that people will throw themselves into a new architecture unless there are seriously compelling reasons.
This holds doubly if not trebly true for an enterprise desktop estate. If everything hasn't been thought through and tested, it could prove an expensive mistake.
The good news is that the OS and processors, plus a huge range of drivers, are now available in 64-bit versions, and have been for five years or more; the problem is going away.
So what's the benefit of 64-bit computing? It's one of those questions to which there's always going to be several answers, but only one clear plus point right now: more memory.
A 64-bit-wide memory bus means that computers can access more memory addresses than under a 32-bit regime. Thirty-two bits equates to 232 memory addresses so those legacy machines can, with a few exceptions, access a maximum of 4GB. Some of that is unalterably allocated for system use, making the real-world maximum for user programs just over 3GB - not much with today's memory-hungry applications.
Compare that to a 64-bit machine which can access 264 addresses. This is far more than the 64-bit version of Windows 7's 192GB memory limit and even further beyond the 16GB that the average desktop PC can accommodate. For the record, the theoretical 64-bit maximum address space is 16.8 million TB, or some 16 exabytes.
In practice, not only will no desktop applications need that sort of memory space until today's desktops have become the day after tomorrow's doorstops, the other benefit of 64-bit computing – improved performance – has little impact right now for most users, although it will do over time.
That's because most applications today are compiled as 32-bit code for 32-bit hardware for the sake of compatibility, but all the hardware, operating system, applications and drivers have to be 64-bit for the benefits of the new architecture to show – although you can use kit like WOW64 to run 32-bit apps in Windows. In other words, once all internal pathways inside the computer are 64-bit, then users should experience a tangible performance boost.
Today, 32-bitness still rules in many areas and acts as a bottleneck, in much the same way as the fat water pipe to your house can only deliver as much water as the thinnest pipe between it and the tap will permit.
While this situation's likely to last for at least two to five years, there are exceptions. If you or your users work on large files in applications such as AutoCAD, Excel or Photoshop, where file sizes can easily breach 4GB, working in a 64-bit computing space can bring big performance benefits, as the system doesn't have to try and cram a large file into less memory than is physically available .
And 64-bit is the future, so it probably makes sense to move in that direction today to avoid awkward and expensive upgrades in the near future, especially since there's little or no reason not to unless you use specialised hardware and drivers.
But some things never change when it comes to deploying desktops: test, test and test again, and even then, someone will want to show you why it's a bad idea, even though, in general, it isn't. ®