The world of high-end desktop processors never stops spinning, and AMD and Intel continue to trade blows in a high-stakes game of one-upmanship. Like the Olympics, this is the area of elite performers, not curtailed by factors such as cost or value, and instead locked in on the goal of getting faster, higher, stronger. In this latest round of ultra high-end processor wars, AMD has released the greyhounds, and offers up what may be the fastest desktop processor ever, the Athlon 64 FX-55. This 2.6 GHz monster looks ready to eat Pentium 4 Extreme Edition processors for breakfast, and then start on the rest of the Intel menu. AMD follows this up with the Athlon 64 4000+, which does upgrade performance in the Athlon 64 line, but might not have the architecture you anticipate.
The Athlon 64 3800+ started the Socket 939 revolution, and introduced a high-end AMD64 processor that could use industry-standard DDR. Its architecture also differed from the enthusiast-level Athlon 64 FX line, as the Athlon 64 3800+ sported 512K of L2 cache, compared to 1-MB for the Athlon 64 FX-53. This was important because the processors ran at equivalent 2.4 GHz clock speeds, and the extra cache gave the Athlon 64 FX its performance advantage. AMD also produced the Athlon 64 3500+, a lower-speed 2.2 GHz model also featuring the same 512K of L2 cache.
The Athlon 64 4000+ moves away from this dual-tiered architecture, and instead of the logical 2.6 GHz/512K release, it incorporates 1-MB of L2 cache and runs at 2.4 GHz. This was a bit of a surprise to us, especially as the Athlon 64 4000+ is, at its core, simply a repositioned Athlon 64 FX-53. The base specifications are the same (both models feature 128K of L1 cache), and while AMD is sticking to its guns and "retiring" the existing Athlon 64 FX-53 when the FX-55 is released, it looks like the old FX cores are being demoted to the Athlon 64 line. The only real difference between the Athlon 64 4000+ and the Athlon 64 FX-53 is that the latter is an enthusiast part, and ships factory unlocked.
This is both good and bad, as the Athlon 64 FX represents the cream of the performance crop, but it still brings up questions regarding the Athlon 64 4000+ model numbering, especially when compared to the 2.4 GHz Athlon 64 3800+. AMD did this once before in their Socket 754 line, releasing a 2.0 GHz Athlon 64 3000+ with 512K L2 cache alongside the 2.0 GHz Athlon 64 3200+ with 1-MB of L2 cache. We all know how that turned out, and we'll be keeping a close eye on the benchmarks to see how the updated AMD model numbers stack up.
The Athlon 64 4000+ may not bring a lot new to the table, but the Athlon 64 FX-55 more than makes up for it. This is the anticipated release, and the Athlon 64 FX-55 sports a full 1-MB of L2 cache and runs at a whopping 2.6 GHz clock speed. This is old school at its best, and the higher clock speed not only provides a nice boost for internal processing, but also translates into a 2.6 GHz CPU to memory controller speed. Otherwise, it's a pure speed upgrade from the Athlon 64 FX line, and in addition to cutting-edge performance, the Athlon 64 FX-55 also ships unlocked for enthusiast overclocking. We're anticipating superior performance from the Athlon 64 FX-55, as it is potentially the fastest desktop processor ever.
The Athlon 64 FX-55 and 4000+ Socket 939 processors use a 0.13-micron SOI process, and now with both incorporating 1-MB of L2 cache, the transistor count is 105.9 million for each. These feature integrated 128-bit memory controllers and utilize a bi-directional HyperTransport link at a 2.0 GHz speed. Both processors use a 1.5V nominal voltage, but differ in terms of thermal and current requirements. The Athlon 64 FX-55 has a maximum thermal power of 104 W and a maximum processor current of 80A, while the Athlon 64 4000+ has slightly lower 89W and 57.4A specifications. Both processors also have support for AMD features such as Cool 'n Quiet, Enhanced Virus Protection, and AMD64 64-bit computing.