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Athlon 64

AMD may be regarded as the second largest CPU manufacturer in the world, but in the race to produce the first 64bit desktop processor, the Texas based CPU giant has taken first place.

In fact the Athlon 64 is not even AMD’s first 64bit CPU. The Opteron (targeted at servers and workstations) was launched earlier this year with much fanfare and the Athlon 64 has a lot to shout about too, representing the dawn of 64bit computing for all.

But what will the launch of 64bit desktop computing mean to you, the user?

The basic idea of the Athlon 64 is quite standard and unexciting but it’s packaged in a radically different way.

Building on the success of the Athlon and Athlon XP product lines, AMD has brought the world of 64bit computing, usually a domain reserved for high-end workstations and servers onto the desktops of homes and offices.

Rather than being a simple "speed bumped" Athlon XP, the Athlon 64 has the ability not only to address more RAM (one of the principle gains of moving from 32 to 64bit) but also the ability to run any current program alongside a 64bit one faster than ever before.

It’s this ability to run unoptimised 32bit programs that makes the Athlon 64 such an exciting technology. With this backward compatibility AMD knows that anyone who buys an Athlon 64 based PC can happily run all their current software, safe in the knowledge that when 64bit applications start to appear they’ll be ready and waiting for them.

Intel, AMD’s arch rival, knows all too well about the problems of backward compatibility. Intel launched the Pentium Pro CPU back in the mid nineties expecting operating systems and applications to have migrated to a 32bit platform. Unfortunately the software market was somewhat behind Intel, and the Pentium Pro proved to be slower than a standard Pentium in a 16bit environment, making it a very expensive and slow solution for most applications. This relegated the Pentium Pro to being almost solely a server chip.

AMD has clearly learned from this and created the Athlon 64 to be fast and efficient both now and tomorrow.

Building on current x86 technology, the same basic technology that is present in the Pentium 4 and Athlon XP (among other processors), AMD has added extensions which allow for 64bit operation. These extensions only become available if both the operating system and the program being run support the Athlon 64 directly.

Perhaps the most intriguing part of the 64bit revolution is what effect it will have on your every day computing experience. If all you use your computer for is surfing the Internet, using a word processor and sending email then the Athlon 64 isn't going to change your computing world too much. However, that doesn’t mean that there isn’t a strong case for the move to a 64bit computing environment.

Many server vendors have been producing machines with 64bit processors for years and reaping the benefits like extended memory addressing. The traditional memory limit for 32bit processors is 4GB, and although this may seem like a huge amount, large servers can require far more.

However, few desktop machines will require more than 4GB of system memory, at least not for a while anyway. So, for the Athlon 64 large scale memory addressing isn’t likely to be a major selling point, but thankfully that isn't the only trick that the Athlon 64 has up its sleeve.

Critical to the success of 64bit computing is operating system support. Many flavours of Unix already support a number of 64bit architectures with the most popular, Linux already providing support for the Opteron and Athlon 64 in the 2.4 kernel. Having the support of Linux is important in the server workspace, but Microsoft operating systems still rule the desktop roost and without the Microsoft seal of approval AMD could face some problems.

Microsoft has already announced, but not christened its 64bit desktop operating system. Microsoft’s 64bit OS is still in the beta testing faze and there still hasn’t been a launch date announced. This means that Athlon 64 early adopters will have to utilize that 32bit backward compatibility mentioned earlier.

Intel hasn’t entered the 64bit desktop market yet, but this isn’t because Intel doesn't have a 64bit processor in its portfolio. In fact the Intel Itanium 64bit CPU has been around for some time. But, Itanium, now in it's second revision only supports 64bit code so you wouldn't be able to run your current version of Windows XP or any other program that hasn't been "recompiled" directly to support this architecture. Herein lies one of the major problems facing anyone who wants to use an Itanium CPU in a desktop system.

There’s no need for any recompiling of source code to run 32bit applications on the Athlon 64 though. Whether the processor is running 32 or 64bit software makes no difference to the user and should be completely transparent.

Big name developers have already pledged their support for the Athlon 64 with Jim Allchin, the man responsible for Microsoft’s operating systems saying that there are ’dramatic performance advantages’ when programs are written specifically for 64bit processors.

The developer of the Unreal and Unreal Tournament games EPIC, has already announced that an updated version of Unreal Tournament 2003 will take full advantage of the Athlon 64. And bold statements from Epic claim that user will be able to see ‘beads of sweat’ on their opponents as they blast their way through frag fests.

Earlier this year we saw the launch of the Opteron. Essentially sporting the same core technologies as the Athlon 64, the Opteron is aimed at high-end workstations and servers.

The difference between the two processors is the number of HyperTransport links that are present and memory support. On an Opteron we find 3 of these links active (for multiprocessor support) whereas on an Athlon 64 there is only one.

Frequency is likely to be higher but this should not be misconstrued as the only judge of performance.

The Athlon 64 marries old technology in the shape of 32bit x86 architecture to a radically designed processor where raw performance is not the only factor at which it excels. There is already widespread support from chipset vendors like VIA, Ali and nVidia, while motherboard manufacturers have already announced products to accommodate the new chip.

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