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AMD's Athlon 64 FX-57 processor

The baddest one-cylinder engine ever
— 12:00 AM on June 27, 2005

IT MAY BE AMONG the last of a dying breed. The Athlon 64 FX-57 is AMD's latest and greatest single-core enthusiast-oriented CPU, a 200MHz clock speed bump in an era when such an increase is becoming more of a rarity than a regular event. This single-core monster runs at 2.8GHz, which is awfully fast in the world of AMD K8 processors. It also packs a handful of revisions that make it more potent, clock for clock, than its predecessor, the FX-55.

The question is: does this chip, which may have the single fastest x86 CPU core ever, have any appeal compared to the slick new dual-core processors from AMD and Intel? We've compared it against a dozen competitors in order to find out.

Getting to know the FX-57
The Athlon 64 FX-57 isn't hard to get your head around. It's an Athlon 64 with 1MB of L2 cache that drops into a 939-pin socket and runs at 2.8GHz. As you might expect, it looks about like so:

Our centerfold

Nothing too different there. Lurking under that sexy metal cap, however, is a somewhat revised K8 core. We've already discussed the enhancements AMD has made to its newer revision E K8 processors in our review of the Athlon 64 "Venice" 3800+. The two cores of the Athlon 64 X2 are both fortified with the same new vitamins and minerals. Now, rev-E goodness comes to the Athlon 64 FX-57 in the form of the "San Diego" core. Like other rev-E chips, this core is manufactured on AMD's 90nm fabrication process with the help of Silicon-on-Insulator (SOI) and Dual Stress Liner technologies. Previous FX chips were made on a 130nm process, so this is a die shrink.

If all goes as one would hope, the die-shrunk chip should be smaller, run faster, consume less power, and cost less per chip to manufacture. Things haven't always gone that way in the move to 90 nanometers, though, which is why CPU makers are exploring alternative approaches like multicore processors.

In addition to the manufacturing changes, AMD has added several things to the rev-E chips, including support for SSE3 instructions, a more flexible memory controller, and improved memory mapping and loading. Revision E cores have typically performed better, clock for clock, than older K8 cores. Part of the reason for the higher performance may be a faster L2 cache, and it's possible AMD has enhanced the mechanism that speculatively prefetches data into that cache. Ask AMD about these things, however, and they go enigmatic on you. So we'll have to ponder that question a little bit.

Like prior FX processors, the FX-57 has an unlocked multiplier for easy overclocking. Unlike in the past, however, the FX-57 does not replace the previous FX and take its place alone atop the product line. Instead, the FX-55 will continue as AMD's 2.6GHz product at a lower price. Here's how the pricing will line up.

CPU Price CPU Price CPU Price CPU Price
Pentium 4 630 $224 Athlon 64 3200+ $194
Pentium 4 640 $237 Pentium D 820 $241 Athlon 64 3500+ $272
Pentium D 830 $316
Pentium 4 650 $401 Athlon 64 3800+ $373
Pentium D 840 $530 Athlon 64 4000+ $482 Athlon 64 X2 4200+ $537
Pentium 4 660 $605 Athlon 64 X2 4400+ $581
Pentium 4 670 $851 Athlon 64 FX-55 $827 Athlon 64 X2 4600+ $803
Pentium 4 XE 3.73GHz $999 Pentium XE 840 $999 Athlon 64 FX-57 $1031 Athlon 64 X2 4800+ $1001

Yep, the FX-57 costs more than an Athlon 64 X2 4800+. That means you can pay 30 bucks more for one 2.8GHz K8 core than you would for two similar K8 cores running at 2.4GHz in the X2 4800+. Whether or not this proposition sounds like a good deal to you will depend a great deal, I suppose, on how you read the benchmarks on the following pages. AMD is positioning the FX-57 as "the gamers' CPU of choice," and that makes sense given the single-threaded nature of most current games. For single-threaded apps, the FX-57 seems like a shoo-in to be the fastest CPU in town. Let's test that theory.