A Guide to The "New" AMD
Last updated: 6/11/00
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
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
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...
Next - The CPU Architecture >