Despite all the recent talk about dual-core processors, it'll still be a year or more before they're widely available as desktop CPUs. The march of processor technology comes in many forms: Process size shrinking and materials changing, caches changing, major and minor architectural enhancements, and of course, clock speed increases. The most interesting new CPU launches contain several of these elements--perhaps a shrink from a .13 micron manufacturing process to .09 along with an increase in cache size and a tweak to the CPU's branch prediction logic. The least interesting are the mere clock speed increases, and that's what AMD has in store for us today.
Like the Highlander, there can only be one Athlon 64 FX processor on the market at a time. The Athlon 64 FX-53's introduction came with the halt in production of the FX-51. So, too, does today's release of the FX-55 mean the end of the line for the FX-53--but in name only: This time around, AMD has essentially renamed the FX-53 as a standard Athlon 64 chip, the 4000+.
The new 4000+ is made in exactly the same way as the FX-53, on exactly the same .13 micron manufacturing process, runs at the same 2.4GHz clock speed, has the same L2 cache size of 1MB, and is available only in socket 939 format. The one small difference between an Athlon 64 4000+ and FX-53; the FX line of chips allows the clock multiplier to be overclocked, while the normal line does not. Since we won't be overclocking our chips in this review, the two chips are interchangeable.
So what's new in the FX-55, then? Not much. AMD has managed to increase the clock speed another 200MHz, to 2.6GHz, keeping them a full 1GHz behind Intel's best. The FX-55 is made with the same .13 micron manufacturing process, and we don't expect to see FX chips made with the company's new .09 micron process until 2005.