Availability: starting June 5th

Web: www.amd.com

Over the past twelve months we've covered AMD's much-talked-about seventh-generation microprocessor: the Athlon "Classic" (as we'll call it from now on).

Today's review focuses on an Athlon 1GHz, but one with a 'difference' (and we promise not to mention Jerry Anderson more than twice). While the Athlon "Classic" was hampered by the "K75" core's off-die cache, wherein the faster the frequency, the more difficult it became to find SRAM L2 cache chips that could run at even half-speed. Hence, after the 750Mhz Athlon "Classic", the "Pluto ratio" (2/5) was utilized, causing the gap between a Pentium III and an Athlon "Classic" equivalent to widen.

All the previous Athlons that we have reviewed were based upon this "K75" core and BGA "Slot A" package, whereas this new "Socket A" chip is based upon the "Thunderbird" core and its full-speed, on-die L2 cache.

If you happen to have a photographic memory, you may recall one or two of these pointed phrases, lifted from various Sharky Extreme Athlon "Classic" reviews,

We moaned:

"Dubbed Pluto 2.5, we can only guess the AMD engineers secretly wished to call this cache divider Goofy. All jokes aside, our 850MHz Athlon endured a similar fate as the Athlon 750 and 800 before it and has an L2 cache set at 2/5 of the core frequency, or 340MHz." - Athlon 850MHz Review

"Performing marginally better than Intel's 800MHz Coppermine, we see where the need for a full speed L2 cache is expressed. At 333MHz, the cache simply isn't able to deliver information to the core fast enough." - Athlon 1GHz Review

"In barely inching past the 800MHz Coppermine, we again see where an on-die cache would be of great utility. With SSE and an on-die cache, the Pentium III is able to maintain a clock for clock advantage running 3D rendering routines equally optimized for both processors." - Athlon 1GHz Review

Well ladies, the full-speed, on-die L2 cache is the meat of the "Thunderbird" story. It's what separates the new Athlon from the Athlon "Classic".

All previous Athlons came with 128K of L1 cache and 512K of external back cache running at half the speed or even less (the Pluto ratio) of the processor's core. The L2 cache has been halved from 512K down to 256K, thus "Thunderbird"-based Athlons come with a total of 384K internal system cache.

By finally enabling full-speed, on-die cache, the old "Achilles heel" of the Athlon "Classic" has been operated on and cured. As ZD BOP's Winbench 2000 Processor Test (an L2-cache taxing benchmark) has shown, AMD's 1GHz Athlon can now go toe-to-toe with Intel's 1GHz Pentium III.