AMD's K6-2 Challenges Intel for 3D
by Alan Zisman (c)
published in Canadian Computer Wholesaler, August 1998
Ironically, at almost the same time that the US
that it was investigating chipmaker Intel for monopoly practices, one
Intel competitors announced its latest and greatest CPU.
Advanced Micro Devices (AMD?www.amd.com) officially
announced its K6-2
processor at Atlanta?s Electronic Entertainment Expo, releasing 300 and
333 MHz models, with plans to boost performance to 350 and eventually
MHz in the third and fourth quarters of the year. (Intel Pentium IIs
available running at 400 MHz). The new product line features a number
enhancements in addition to raw CPU speed.
This chip marks the first time that one of Intel?s
competitors has gone
beyond simply cloning the feature set of an existing Intel product. The
K6-2 is the first chip to offer 3DNow!, a set of multimedia and 3D
that go well beyond the MMX instructions offered by Intel and current
"For the first time, AMD has introduced a processor that is
not solely by megahertz or price but by innovative technology that
a new level of 3D performance and realism," said S. Atiq Raza, AMD
vice president and chief technical officer. The 3DNow! instructions
also be available in upcoming chips from Cyrus and Centaur, as well as
While Intel is working on a similar set of 3D
instructions, they will
not be compatible with 3DNow!. The result is a window of opportunity
Intel?s competitors, where they will be offering products that are, in
this way, at least, more advanced than Intel?s offerings. But there is
a catch?3DNow!, like MMX, only provides improved performance in
that is written to take advantage of it. Microsoft has promised support
for 3DNow! in their next-generation, DirectX 6.0; as a result, any
(primarily games) written to use DirectX 6.0 will automatically provide
3DNow! support. Software written to take advantage of the OpenGL 1.2
3DFx Glide programming specifications will also support 3DNow!.
3DNow! offers 21 new processor instructions,
characterized as Single
Instruction Multiple Data, directed at speeding up the interaction
the CPU and a 3D accelerator card, and promising to deliver up to four
floating point instructions per clock cycle.
In addition, the K6-2 will, like the newest Pentium-II
motherboards running at 100 MHz bus speeds. This results in increased
across the board, not just for CPU-intensive tasks. (Note, however,
best performance at 100 MHz, regardless of the CPU, requires faster
which is currently more expensive that RAM that only has to keep up
66 MHz motherboards). Expect performance increases of 15% or more,
to a 100 MHz motherboard.
Like its predecessors from AMD and the other Intel
K6-2 relies on the Pentium-style Socket 7 design, but the new product
require an updated version, known as the Super7 Platform. Along with
high-speed bus, Super7 designs will support AGP graphics adapters,
now, only available on designs based on Intel?s Slot 1 for Pentium-II
Despite the enhancements, AMD?s product continues to
lag behind Intel?s
Pentium-II line in a number of ways. While AMD claims the K6-2
as much as four times as fast as a P-II in 3D-intensive operations
properly written software), and while its integer instructions (used in
typical business software) are comparable to the P-II?s, the K6-2
inferior to the P-II line in running standard floating point
lagging behind by as much as 50% on standard benchmark tests.
As a result, many popular games that have not been
written to take advantage
of the K6-2?s new instructions will run better using Intel iron. Even
low-priced Celeron offers all the floating point power of a full P-II
was pointed out to me by reader Art Prufer).
And while, given a 100 MHz bus (and high-speed RAM),
systems built around
either a P-II or a K6-2 will access memory at full bus speed, a
has the advantage in the speed that it accesses its L2 cache. With the
cache built onto the P-II?s cartridge, it is accessed at half the
speed?175 MHz for a 350 MHz processor. On K6-2 systems, the cache is on
the motherboard, and is accessed at the motherboard?s speed?100 MHz
of the processor speed. In many cases, the difference in cache speed
result in a noticeable difference in overall system performance.
Recently, a shootout was set up between similarly
priced K6-2 and P-II
systems, comparing performance on a number of cutting edge games.
Rather than comparing systems with the same speed
processors and motherboards,
the test team put a 333 MHz K6-2 on a 100 MHz motherboard up against a
300 MHz P-II in a 66 MHz motherboard?this enabled them to compare
that were roughly at the same price-point. (The 100 MHz BX motherboard
required for the higher-speed P-II systems costs about twice as much as
the 66 MHz LX boards, which are about the same price as the Super7
They used pre-release versions of DirectX 6 and tested games such as
upcoming Quake2, offering 3DNow! Support, as well as others that lacked
Their results? About 10% better performance for the
K6-2 when running
games (such as Quake2) offering direct support for its features. When
support was not built into the game, however, 3DNow!, still provided
K6-2 more or less parity with the Intel system, evidence of the effects
of DirectX 6.
AMD believes that it has overcome the production
difficulties that have
sometimes limited supplies of its processors; all K6-2s are being
at on .25 micron wafers, offering increased yield.
Looking for still more evidence that the market has
opened up more fully
for Intel?s competitors? With HP?s announcement that it will ship AMD
in some of its Pavillion-series computers, virtually all of the major
name computer manufacturers offer one of the non-Intel processors in at
least part of their product lines.
And with the K6-2 as the first non-Intel 80x86-type
CPU to go beyond
Intel?s feature set, there?s evidence that the one-time cloners are no
longer contents to stay a generation behind Intel, aiming for the
of the market.