Introduction

The first Athlon 64 FX processor debuted a little more than one year ago and AMD hasn’t looked back since. Even after Intel retaliated with its Extreme Edition family, the Athlon 64 FX maintained a performance advantage and came in at a lower price to boot. Since then we’ve seen increased operating frequencies and a transition from Socket 940 to the more user-friendly Socket 939.

Indeed, very little has changed within the AMD64 architecture. Most of the improvements have been external: adding support for unbuffered memory at the high-end, keeping up with Intel’s platform improvements by way of enhanced Serial ATA, Gigabit Ethernet, and multi-channel audio support, and boosting the 800 MHz HyperTransport link up to 1 GHz.

While that last improvement didn’t seem to do much for existing AGP chipsets (there aren’t any components capable of saturating 8 GBps on the desktop), it will come into play more in the near future. The big news for the rest of 2004, next to the processor announcements transpiring today, is a progression towards PCI Express core logic. Both the Athlon 64 FX-55 and Athlon 64 4000+ are enabled with those 1 GHz HyperTransport links, which will match up well to NVIDIA’s upcoming nForce4 chipset and its ancillary subsystems.

The Athlon 64 FX-55 and A64 4000+

Bottom of the chips

But of course, the real news here today is a pair of processors that will carry AMD into the holiday buying season and past Intel’s upcoming platform revision, it hopes. Dubbed the Athlon 64 FX-55 and Athlon 64 4000+, the two chips bear a lot of enthusiast appeal and promise to improve gaming through minor bumps in frequency.

Athlon 64 FX-55

Indeed, the incremental model number update from FX-53 to FX-55 represents a straight frequency increase and nothing else. Formerly at 2.4 GHz, the new flagship in AMD’s flotilla runs at 2.6 GHz. And while a handful of AMD64 processors have made a jump to 90nm manufacturing, the latest Athlon 64 FX is still etched used Fab 30’s 130nm process. It does, however, incorporate AMD’s first implementation of strained silicon-on-insulator, which improves the switching performance of transistors by increasing the drive current in N- and P-transistors. There aren’t any official announcements on the technology to speak of, but representatives at AMD claim that the company will discuss it further in the future.

As a result of the silicon process changes, the Athlon 64 FX-55 features different power specifications than either of its predecessors. Maximum heat dissipation is now up to 104W from 89W previously. Apparently, that’s enough of a difference to warrant a new cooling spec too, as the heatsink that shipped with AMD’s evaluation sample included an array of four heat pipes to accelerate the dissipation of heat across its aluminum fins. The heatsink is manufactured by AVC, who currently claims that there aren’t any plans to take the product into retail. However, other companies, specifically Thermaltake, claim that many existing heatsinks should suffice (we confirmed its own Venus 12 works well, even in an overclocked environment). AMD’s Damon Muzny also notes that all retail Athlon 64 FX-55 processors include an approved cooling solution.