Let the Quad Core War Begin
Original Article Date: 2007-09-17
AMD launched their long awaited "Barcelona" quad-core Opteron CPU
just a week ago. Hyped
as the world's first "true" quad-core (four CPUs on a single die of silicon), AMD
claim that this design outstrips in performance the pseudo quad-core design of Intel's
The war already began last month with Intel slashing the cost of their Clovertown
CPUs, in an attempt, I believe, to spoil AMD's Barcelona launch. It's
hard to believe Intel are making any profit over the sale of these CPUs. Either
that, or they were making a small fortune in selling the dual-core Woodcrest models,
since the pricing of the quad-cores was dropped to within 20% of the equivalent
So this price drop may be temporary. But then again, it may be permanent. Intel
has already released the Core CPU built on the more efficient 45nm (nanometer) process
technology (look out for next month's article "What's in a Nanometer?"),
and this 45nm technology
is expected to appear on the Xeon line of processors in late Q4 '07. I see Intel
lining up AMD for a one-two punch in this regard. Since, with AMD having only just gone over to 65nm technology, and Intel commanding ten times the market capitalization
of their smaller competitor, AMD are looking vulnerable. But then one thing that
AMD have shown us in the past is that, despite the odds of being the underdog for
more than a decade, they are a survivor.
Barcelona is a chance for AMD to play catch-up once more. It's a critical launch
for AMD. But does the hype live up to real-world performance advantage?
Barcelona's four CPU cores on a single slab of silicon - a world first
The big headline about AMD's new chip is the fact that it's the world's first
true quad core CPU. With all four cores etched onto the same piece of silicon, this is
expected to bring benefits in terms of reduced latencies and wider data bandwidths
between the cores and the multiple caches and system memory.
Compare this with Intel's "Clovertown" quad-core CPU. Intel's chip is in fact two dual-core CPUs
wired together. So AMD's claim of being the world's first true quad core CPU is, indeed valid.
Other differences with Clovertown lay in Barcelona's incorporating the memory controller
(or "northbridge") on-chip, instead of on the motherboard. This tradition began
way back in 2003 with the first generation of Opteron processors, and has the advantage
of reducing latencies between CPU and system RAM. However, it does have a price,
and that is one of real estate. As can be seen on the picture to the right, the
memory controller takes up significant and precious space on the chip. And this
is perhaps one of the reasons why they had to reduce cache size.
Briefly, a cache is a small amount of very high speed memory that stores data that
is frequently used and on a repeat basis by the CPU. By storing such data in this
highly local and lightning fast memory, the CPU does not have to make comparatively
long trips to the main system RAM for most of its commands, thus improving performance
significantly. Typically, CPUs have an L1 and L2 cache. The tiny L1 execution cache (in Barcelona's
case, 64K) sits inside each core, and stores the most frequently
used CPU data.
The headline cache figure you see with CPUs is the L2 cache - in
Barcelona's case 512K per core (i.e. 4x512K = 2MB). This L2 cache size might not sound like as
much as Clovertown's giant 8MB (2x4MB) caches, and generally speaking, the bigger
the cache, the better the performance. But AMD claim that their dedicated
small cache operates more efficiently than the shared cache of Clovertown.
Furthermore, AMD have broken with tradition in putting
an L3 cache
on-chip - 2MB in size. Typically a CPU either has no L3 cache at all, or it is placed
on the mainboard, close to the CPU. By moving the L3 cache to the CPU die itself,
AMD believe this will provide more optimization of cached-data, and more efficient
and faster CPU operation.
AMD claim a number of other innovations, such as
is the ability of a CPU to be able to run more than one operating system simultaneously,
using special software, and is becoming increasingly popular as hardware power continues
to outstrip software need. With virtualization, system admins can run a web server,
a mail server, and a file server, for instance, all on the same box, running simultaneously,
but on totally separate instances of, say, Windows 2003, or Redhat Linux. By providing
optimization code for virtualization, AMD are acknowledging and looking to gain
more of an advantage in this increasingly popular method of maximizing server hardware
Squaring Up with Intel's Clovertown
The following table shows the full list of quad-core CPUs available from AMD as
of the launch date:
AMD's line-up of quad-core CPUs on launch
Max Power Usage
Simultaneous Sockets Supported
As you will likely notice, there is not a huge amount of choice available at this
time, with clock speeds falling within the 1.7-2.0GHz range. This was somewhat disappointing,
as I'd hoped that AMD would be sporting the 2.6GHz model that AMD had quoted in
a number of their own benchmarks. This higher speed model would have been necessary
to compete directly with the fastest Intel Clovertown model, the Xeon 5365 operating
at 3.0GHz clock speed. AMD have promised that higher speed CPUs will become available
over the next few months. Let's hope they live up to their promise.
How does this line-up compare in terms of price and performance
with Intel's quad-core Clovertown? Well, there is no comparison in the 4/8-Socket
HPC (High-Performance Computing) space, where AMD dominate. AMD's launch of
quad-core 4-way and 8-way supported CPUs will continue to enhance the affordability
and performance of this growing market segment, which was once the preserve of Cray
and IBM supercomputers.
But in the much larger 2-socket segment, AMD must clearly demonstrate their ability
to compete with Intel's dominant Clovertown Xeon CPUs.
Early benchmarks in a number of online test sites such as Tom's Hardware Guide and
Anandtech suggest that in some tests AMD's Barcelona significantly outperforms Intel's
Clovertown at the same price point, while in others, it lags. The current consensus?
They're about even.
Sadly, AMD, really needed to demonstrate that their inclusion of four cores on a
single die (instead of Clovertown's gluing of two dual-core dies together) would
have resulted in a significant and commanding lead in performance over Intel's Clovertown.
Early benchmarks indicate that this has not happened, and so I believe that Intel's dominance of
the 2-socket CPU market is likely to continue.
That said, many workstation customers of mine specifically
prefer Opteron over Xeon, citing better stability and software compatibility.
Having quad-core CPUs to choose from for future purchases (and also for possible upgrades to existing dual-core workstations), and knowing that these new CPUs are
at least on a par with Intel's equivalent, is great news for AMD-loyal customers.
Upgrading from Dual Core to Quad Core is Simplicity Itself
An important advance has been that AMD have been able to double the number of cores
on each die, without increasing the power consumption of the chip.
Due to excellent future planning from AMD, the Opteron Socket F design has
complete forward compatibility built into it, enabling system admins and individual users to double the computing
power their existing server and workstations with just a single CPU exchange and a BIOS update. No
new heatsinks, system fans or power supplies are required.
Combined with our offer to buy back your existing dual core CPUs at the time you
buy your quad core Barcelona CPUs, you will find that doubling your system's processing
power can be a lot cheaper than you could imagine!
Barcelona and the Future of AMD
The long awaited launch of Barcelona has enabled AMD to get back
in the game again. They will continue to dominate the 4/8-socket High Performance
market. But because of apparent relative parity in performance with Intel's quad-core chip
in the 2-socket mainstream server and workstation arena, I expect that AMD will
continue to play second fiddle to their bigger brother, which has had quad-core
chips available since January of this year.
And what AMD need right now, more than anything, is a good shot in the arm. I don't
think this happened with their quad-core launch. This is sad, because if AMD don't
claw back some market share, and get some return on all the investment they have
put into developing Barcelona and its 65nm technology, their mounting losses could continue, leading them
into even stormier waters financially. The last thing that
I, and I'm sure you, would want
to see, is the loss of a major competitor to Intel.
It is ironic that we have AMD to thank for the tremendous processors we have
from Intel today. Three years ago, the server CPUs Intel were producing were lackluster,
workmanlike, average at best. But AMD's far superior Opteron kicked them out of
their complacency, and made them fight back.
If AMD go under because of a potential failure of Barcelona to pull them out of their
financial difficulties, then we have a monopolistic Intel future to look forward
to once more, and the technological stagnation and poor value that always results
from monopoly, accompanying it. And I don't know about you, but that prospect simply
makes me shudder.
Let's continue to wish for competitive times in the CPU marketplace.
Chief Systems Engineer