While 64-bit computing has been around for a while (for the two of you who could afford Intel's Itanium, and now Itanium II processors), the dream of 64-bittery for the humble home system has been a long time coming. With both Apple claiming the first commercially available 64-bit desktop and AMD also claiming this accolade, it'll be an interesting time ahead for us power-hungry pundits.

We're currently waiting for an Apple G5 to benchmark before we deliver a verdict on that one, so while Apple claims G5 'availability' we happen to think that this 'availability' should entail some form of being able to purchase one, not place a back order. The flipside of this is that as we go to press, the AMD Athlon 64 should be ready for mainstream purchasers off the shelf.

So why should you care? 32-bit processing has served us well, so why the rush to 64-bit computing? To work out who the Athlon 64 processor is for, it's important to cover what exactly 64-bit processing is, and does, and we'll start with the basics.

64-bits ain't 32-bits x 2

A 1GHz 64-bit processor is not the same as a 1GHz 32-bit processor only twice as fast. In fact, a 64-bit processor at 1GHz is more analogous to a 32-bit processor at 1GHz than anything else; it's what the system does with those extra 32-bits that makes all the difference.
And in general, it comes down to the operating system and what the software you're running does.
So why would you want a 64-bit processor over your current 32-bit one. Depending on who you ask, there are plenty of pros and cons for both sides of the fence many are currently still sitting on.

Taking a less aggressive approach than Intel's Itanium II development,
AMD's Athlon 64 FX-51 is dual purpose, allowing for 32- and 64-bit hardware processing, offering the best of both platforms.

The preview unit we received was decked out in a pretty groovy looking CoolerMaster TAC-T01 ATX case with green cold cathode. Very AMD. Boasting that 'power-hungry enthusiasts, gamers and prosumers can explore the full potential of AMD64 technology while enjoying outstanding performance on today's software' we set about putting this to the test. Supplied with a pre-beta copy of Microsoft Windows XP 64-bit operating system, we had trouble from the moment we began, quickly realising that we weren't going to get a successful SYSmark2002 run, the 64-bit Windows determined to mess us around. Unable to be benchmarked in the conventional method, we were forced to seek an alternative testing method, eventually deciding to run CPU intensive testing such as timed Photoshop filter instances and low resolution gaming to stress the processor by forcing it to render images rather than the GPU.

Clocking in at 2.2GHz with a 200MHz front side bus, double pumped to 400MHz, the system was supplied with two DIMMS of 512MB PC3200 DDR-SDRAM, Leadtek A350 FX5900 Ultra and three hard drives, two 10,000 RPM serial ATA drives comprising a RAID 0 configuration and the third an EIDE 7200RPM 40GB disk, all of which was mounted on an Asus SK8N nForce3 Pro 150 motherboard.

AMD believe inclusion of an integrated DDR memory controller reduces DRAM latency and allows for better performance from memory intensive applications. These claims were consistent with our benchmark results, the AMD64 returning results up to a third faster than the 32-bit equivalent scores in 32-bit, non AMD optimised Photoshop 7.0.1.
Low resolution high geometry testing in Quake 3 proved to have mixed results, with the AMD64 holding its  ground by scoring an average of 84.7 frames per second at 640 x 480, leaving the PC Authority test bed to fall behind marginally with an 83.93 average fps total. Still lower resolution testing turned the tables, with 320 x 240 tallies showing a swing in the higher clocked P4 2.53, winning 87.97 frames per second to the Athlon's 75.5.

We were interested in running a more recent game benchmark such as Unreal Tournament 2003 to show a better gaming indication given the target market audience of the technology, but unfortunately UT2K3 is currently unavailable on the Mac platform and would serve as only a stand alone benchmark rather than a comparative and unbiased test of true gaming performance.

The 1MB on-die L2 cache of the AMD Athlon 64 FX-51 combined with SSE2 instruction optimisation makes for a compelling package for the desktop PC market, gamers and power enthusiasts alike. Once a native 64-bit version of Photoshop or synthetic benchmark is widely available with SSE2 enhancement, we're keen to retest and see the real benefits available to the end user.

With a possible pin layout change on the horizon, early adopters might find themselves out in the cold if the 64 FX loses one of its 940 pins and drops down to a socket 393 CPU.
September 24 will see the launch of economically feasible 64-bit computing for the desktop market. We anxiously wait to see how much impact this dual-platform processor will have on the enthusiast system builder demographic.