A Guide to The "New" AMD Socket A
Athlon Processor
Last updated: 6/11/00

"New" Socket A Athlon

"Classic" Slot-A Athlon

Socket A Socket

On June 5, 2000 at Computex in TAIPEI, TAIWAN AMD announced the "New" Socket A Athlon "performance-enhancing on-chip L2 cache memory" processor.  Previously code-named the Thunderbird processor, the "New" Athlon, shown above, right, is a repackaging and performance enhancement of the "Classic" Athlon  shown below it.   The L2 cache' memory which was on two chips separate  from the CPU chip (off-die), but in the same Slot A package, was moved to the CPU chip itself (on-die).  The CPU was then repackaged as Socket A processor.

The L2 cache' on the "Classic" Slot A processor was 512K and ran at 1/2 the CPU speed for slower CPU's and 1/3 the CPU speed for 900 Mhz and faster CPU's.  The L2 Cache' on the "New" Socket A Athlon runs at the CPU speed.  Although the L2 cache' on the "new" Athlon is smaller, the net result, depending on whose benchmarks you read (I'll wait for some widely-available,  production motherboards before running mine), is that the "New" Socket A Athlons are about 7-10% faster than the "Classic" Slot A Athlons.

Another change in this version of the processor is that it is shifting to copper interconnects (traces) in place of the aluminum used in the older processors (or at least it has for processors made in AMD's Dresden Plant).  The "New" Athlons also use a .18 micron geometry and the "Classic" Athlon used .25 and .18 micron processes.  This plus the smaller cache' cuts the maximum thermal power for the new chip, which now contains 37 million transistors, from the 65 Watts of the older processor, which had 22 million transistors on the CPU die, to 54 Watts.  Also, the processor draws a  theoretical maximum current of 33.6 amps versus the 37 Amps for the "Classic" Athlon. 

Like the "Classic" Athlon, the "New" Athlon has 128K of on-die L1 Cache'.

The movement of the L2 cache' to the processor die is not new.  For examples, the AMD K6-III and the Coppermine versions of the Intel Pentium III processors have 256K on-die cache'.  The Coppermine processors have a 256 bit path to the L2 Cache' and both the "Old" and "New" Athlons have 64 bit paths.

The Pentium III processors have likewise moved from a slotted to (or back to) socketed configurations.  The days of Slotted CPUs (or shall I say toasters?) and motherboards appear to be at an end.

The Socket A, Pin Grid Array (PGA) CPU's, which include AMD's new Duron processor,  resembles previous socketed CPU's, such as AMD's K-2, the original Pentiums, and Intel's current Socket 370 CPU's.   A Socket 7 has (had) 321 pins, Socket 370 CPU's have, of course, 370-pins,  and a Socket A CPU has 462 pins.  Good grief!  I can hardly wait to receive my first Socket A processor with bent pins.

The rest of this guide is pretty much a rehash of the one I wrote for the Slot A "Classic" Athlon.   It has been edited, updated, and included for completeness...

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