The AMD 64 has been out a while now, it's a shame that more hasn't been done with this technology. The model I am reviewing has a 1MB cache.

To explain briefly, when people refer to 'bits' in this context, they're referring to how much information the chip can deal with at any one time - 64 bits is better than 32 because more data is being dealt with in one go. (Ok, I know that's really abstracting it all you geeks out there, but I'm just trying to give people a rough idea.)

Most processors used at home these days are still 32 bit, which is fair enough - Windows XP is a 32 bit operating system, and the majority of applications out there have been optimised for this. To be honest for word processing, email and other mundane tasks, 32 bit should be sufficient.

Games, video decoding, high end graphics work and number crunching, however, would make great use of a 64 bit chip.

The thing that puts a lot of people off upgrading is that the 64 bit processors that were previously available were 64 bit ONLY and required special operating systems to operate. The beauty of the latest AMD 64 range is that it is backwards compatible with 32 bit software.

Certain games such as Unreal 2004 and Farcry are touting 64 bit versions of their games - that is one reason to purchase one of these chips, but other than that you will be waiting a long time to see these things taxed.

It runs Windows XP like a dream, and runs the beta version of Windows 64 too. Windows 64 is still very unfinished on the whole, and getting drivers / third party software for it is a nightmare. Once you've got working graphics, sound and network drivers though you can try out some of the special '64 bit' versions of certain programs and feel good about the money you've spent on this expensive piece of kit.

The beta is time limited and a free download - well worth a look for owners of one of these processors. It's AMD only - Intel have their own version but that's not really for domestic use.

I have an Athlon 64 3000+ and a normal Athlon XP 3000+ in this household - there is a slight difference in speed - the chances are this comes more from the larger Cache size of the Athlon 64 (1Mb on this version). The true power of this chip isn't really used by current software yet.

In terms of benchmarks, the 3DMark improved a little because of the improved processor test results, but as 3DMark relies a lot on the graphics card I found this to be a limiting factor. The Final Fantasy 11 benchmark ran on two near identical specced machines saw nearly a 2000 point difference in favour of the AMD 64. (For those who care the difference is in hard drive capacity although both had ample free space - graphics card, memory, etc the same including RAM speed were the same - just the motherboard and processor changed.)

If you buy this processor, you will most likely need to change your motherboard, and you will be making your old fan redundant too - the Athlon 64 is of different dimensions to most of the other processors and the socket is different enough that most old fans won't fit on it.

I would recommend sticking with the fan that comes with the processor for a little while - there are other fans available but they aren't up to scratch yet - the cooling provided by the default fan is actually superior for a change.

The processor comes in a very, very well sealed plastic package, with it's own fan and an installation manual that shows the new, slightly unusual way of putting the fan on. It even has a URL to a video of someone doing it, in case you get confused. The new fan mounting includes a plate on the back of the motherboard, which makes for a very secure attachment.

Other than that, all I can say is fit as normal, install the operating system, and run. It seems to respond fairly well to a little over-clocking (I haven't went too far with it though). and under normal conditions is rock solid stable, if a little warm when under heavy load.

I would recommend this processor - although if you have the money to spend get the FX 53 version, or a slightly faster version of this. There is some future proofing in the fact that this bears the flag of '64 bit' but by the time something in the mainstream actually USES that feature the extra speed may well be welcome.