Deschutes: Notice that real world gain is only 10%
(when you can get 20% on WinNT by correctly setting
your SecondLevelDataCache)
Powerful Pentium IIs: Supercharged Systems -- An
exclusive look at the first systems powered by
Deschutes-Intel's hottest processor yet
By Jonathan Blackwood, Jim Forbes and Owen Linderholm
Intel's new Pentium II processors-code named Deschutes-are here. And
there are two reasons why you should sit up and take notice. The first-hardly
surprising-is that Deschutes will up the megahertz ante and crank up
Windows computing another couple of notches. But the new technologies
that Deschutes brings to the table might be even more significant. In the
simplest terms, Deschutes promises a broad range of Pentium II-based
systems that run faster and cost less. n Our exclusive tests of the first 14
Deschutes-based systems-seven desktop PCs and seven notebooks-confirm
that the industry buzz over this new processor is warranted. It delivers
record-breaking performance now, and is poised to turn in even more
impressive results down the road. n There are four variations of the
Deschutes chip for four distinct uses, so there's a good chance you'll have one
in your PC soon. Deschutes technology will appear across the full range of
PCs: from servers and advanced workstations at the high end, to desktop
systems, to notebooks and all the way down to the burgeoning sub-$1,000
desktop PC category. n The common Deschutes thread is that all these
versions use the same basic Pentium II core manufactured with a 0.25-micron
process-compared with the 0.35-micron process used for all Pentium IIs,
until the recently introduced 333MHz model. The new fabrication process
reduces Deschutes' size, power consumption and cost.
The first type of the new Pentium IIs are mainstream desktops, now available
in 350MHz and 400MHz configurations. A 450MHz version will soon
follow. But the core processor is only part of the story. With these chips, Intel
is also introducing a new chipset-the 440BX-that supports a 100MHz system
bus (compared with the previous 66MHz bus of Intel designs) and faster
Accelerated Graphics Port (AGP) operations. The new bus is already
available on the desktops and AGP capabilities will follow in a few months.
Pentium IIs for notebooks will have a new mobile cartridge in place of the
traditional Slot 1 mounting. These new cartridges use the 440BX as their
main chipset but will stick with a 66MHz bus until switching to 100MHz later
this year. The first Deschutes-powered notebooks run at 233MHz or
266MHz, but 300MHz models will follow soon.
Later this year, we'll also see the other two parts of Intel's new strategy. One
is a set of Pentium II products in 350MHz, 400MHz and 450MHz speeds
aimed at the server market. These will use a bigger cartridge, Slot 2, to hold
up to 2MB of level 2 cache, which will run at the same speed as the
CPU-twice the speed of current level 2 caches. These server CPUs will also
be able to use a 100MHz system bus.
The final version will be a slimmed-down Pentium II that fits in Slot 1. This
pared-down Deschutes Pentium II, called Celeron, will ship in sub-$1,000
PCs. It will come in 233MHz and 266MHz speeds initially, with 300MHz
and 333MHz versions to follow.
Deschutes in Perspective
The immediate impact of Deschutes may not be profound, but the future is
promising. For now, these new chips will raise the top processing speed from
the current 333MHz to 400MHz. That translates into a theoretical 20 percent
improvement in CPU power-but our tests revealed a 10 percent performance
gain for real-world applications. We saw a similar 10 percent boost on the
notebook side comparing the new 266MHz Deschutes Pentium II, the first
Pentium II chip for notebooks, to the 266MHz Pentium with MMX.
The major performance benefit will come when faster versions-450MHz for
desktops and 300MHz for notebooks-arrive. While the speed improvements
are only incremental, features such as better AGP and the 100MHz system
bus will become reality across the board by then. The ability to move data to
and from main memory faster, as well as offload even more graphics
processing to high-power AGP cards, should add a substantial secondary
kick to performance.
The result? On desktops we should see a 450MHz Pentium II with
second-generation (2X) AGP and a 100MHz bus running about 40 percent
faster in real-world performance than today's 333MHz Pentium II. That's a
big jump. Once again, significant improvements in notebooks will lag, since
they won't get the benefit of the 100MHz bus until late this year, and
probably won't get the boost from second-generation AGP until 1999.
Servers and Workstations
This category stands to gain the most from the 100MHz bus and larger, faster
level 2 cache.
The Slot 2 version of Deschutes is expected before the fourth quarter of this
year, perhaps as early as this summer. This CPU will initially come packaged
with 512KB or 1MB of level 2 cache. By year's end, a version of this
package with 2MB of level 2 cache should be available.
To ignite the server market even more, the new Pentium II's were designed to
work in systems with at least four CPUs. In addition, the new chipset allows
for eight-processor servers, which could give companies such as Sun
Microsystems a run for its money in the server market.
The Slot 2 level 2 cache will operate at the same speed as the CPU
(350MHz, 400MHz or 450MHz) instead of half the speed of the CPU as it
does now. Intel is manufacturing its own high-speed Custom SRAM
(CSRAM) to facilitate this.
But faster cache comes at a cost, especially in servers with multiple-CPU
configurations. These systems need a way for each CPU to talk directly to
the level 2 cache associated with other CPUs. That means if you increase the
level 2 cache size, you need to provide more communications pathways off
the CPU module. Faster and bigger level 2 cache also means more power
consumption and more heat generated. The net result is that these CPUs will
come in a new, much larger cartridge to fit in a longer slot.
The new 440BX chipset offers additional benefits for servers. The most
important is Open Page Architecture, a new memory architecture that lets the
CPU access main memory faster. It also offers improved error correction and
recovery, and allows for up to eight concurrent CPUs in a multiprocessor
system.
Mainstream Desktops
The first 450MHz Pentium II will probably appear in a Slot 1 standard
configuration. So, while it might not be able to exploit the larger, faster cache
of the Slot 2 design, the CPU's higher clock rate will plainly mean faster
systems.
But other performance benefits accrue for mainstream desktops as well.
Using the 440BX across the board passes many of the benefits meant for
servers on to other systems. The most obvious of these is support for 2X
AGP. This means the AGP bus is clocked twice as fast and the sideband
channel (a slower side channel for control information) is also used. Current
AGP implementations only use a single-speed main channel and mix control
information with the data.
Combine 2X AGP with a new generation of graphics cards actually designed
to make real use of AGP, and you'll see a considerable improvement in
graphics performance. The memory architecture improvements described for
servers will also benefit desktops, but their impact won't be as noticeable.
Notebooks
As with desktop systems, the main benefit to notebooks will be faster CPUs.
In this case, the move is not immediately to faster clock speeds, but to a
better basic CPU-from the Pentium with MMX to the Pentium II with its
lower voltage and other benefits. You can get a Pentium II notebook at
233MHz or 266MHz, with 300MHz units coming later this year. Intel wants
to narrow the long-standing performance gap between notebooks and
desktops. The main improvement in this area is the use of the same chipset in
notebooks as in desktops. This means all the ancillary benefits are available
immediately on notebooks, even if they can't be used yet because of power
consumption or size limitations.
Second-generation AGP is a prime example of how Deschutes will benefit
notebooks. Graphics performance has always been treated as an afterthought
on notebooks. But with the advent of big, bright, lower-cost active-matrix
screens, notebook displays have become viable for graphics.
Intel is giving notebook makers a chance to jump straight to the
high-performance 2X AGP solution. But it will probably take at least a full
year until vendors take advantage with full-speed AGP in notebooks.
The BX chip also brings full power-management support to notebooks,
which is why Deschutes notebooks have appeared so quickly and with so
little negative impact on battery life. But the new chips do require different
packaging for notebooks-the Slot 1 solution is too big and uses too much
power. The new mobile module, based on the IMM (Intel Mobile Module)
introduced with the recent high-speed Pentium MMX CPUs, is also used for
mobile Deschutes. This makes it easier for manufacturers to produce both
high-end and low-end solutions based on a single design.
Sub-$1,000 Systems
Intel sees this as the fastest growing market area and wants to put its highest-
performance technology here, despite the low cost of the systems. It's also a
market where rivals such as Advanced Micro Devices (AMD), Cyrix and
Integrated Device Technology (IDT) mount their strongest challenges.
Compaq and other major manufacturers have conspicuously chosen non-Intel
CPUs for their low-priced systems.
Intel is fighting back with Celeron-a version of Deschutes that lacks level 2
cache, at least initially. These CPUs will also run more slowly than other
Deschutes versions. That combination reduces the need for radio frequency
and heat shielding, and lets Intel produce these CPUs in a package designed
for Slot 1. The Celeron package isn't a cartridge, but a more traditional (and
cheaper) chip-on-a-circuit-board module. Intel plans a future version with
level 2 cache integrated onto the Pentium II CPU itself, rather than as part of
a Slot 1 module. Initial low-cost Pentium IIs in this market will be clocked at
233MHz and 266MHz, with 300MHz and 333MHz to follow with the
integrated level 2 cache.
The 440BX
The chipset is nearly as important to the whole process as the CPU itself. In
this case, the chipset is two chips-the 440BX and the PIIX4E- which control
memory and peripheral access for the CPU. (See the sidebar "BX in a Box.")
Many of the benefits coming with this round of the Pentium II are attributable
directly to the 440BX chipset and not to the CPU itself, which is
architecturally identical to all previous Pentium IIs.
Intel expects to keep selling its current chipsets, the LX series, for at least
another year. The 440LX works with the company's sixth-generation
processors (Pentium Pro, Pentium II and Deschutes), while its 430TX
supports fifth-generation designs such as the P55C Pentium with MMX.
Intel's move toward a single chipset across its line is a significant step and will
simplify system designers' jobs.
The Ideal Deschutes System
Intel envisions an ideal Deschutes system with at least the following
specifications: 32MB of fast 100MHz SDRAM, true second-generation
AGP support, at least two USB ports and an Ultra DMA hard drive for
faster access. Each of these components takes advantage of specific features
in Deschutes or the 440BX chipset to improve the system's overall
performance. We would add the following for the ideal desktop: 64MB of
RAM rather than 32MB, a 19-inch monitor, a true AGP graphics card with
8MB of video RAM, high-capacity removable storage and
second-generation DVD-ROM.
The Future of Deschutes
Future Intel technologies could tie in with Deschutes. The CPU code-named
Katmai is a revision and expansion to Intel's MMX technology that adds
better support for fast floating-point calculations and should dramatically
improve 3D graphics performance, among other things. Look for this
technology in CPUs in early to mid-1999 (see the sidebar "New Chips, More
MIPS"). Intel has also talked about a 600MHz CPU in the same time frame.
This would be produced either using the new 0.25-micron manufacturing
process or a future 0.18-micron process. It would make sense to include
Katmai in a range of CPUs from the current 333MHz through the current
450MHz and on to the logical extensions, 500MHz, 550MHz and perhaps
the hypothetical 600MHz Willamette system.
Intel also plans a 2MB level 2 cache version of the Slot 2 server Pentium II,
which could eventually be clocked at 500MHz or higher.
More Megahertz for Your Money
With so much advance billing and the resultant anticipation, the newest
versions of Deschutes might seem a bit underwhelming at first. Deschutes' full
potential won't be realized initially. Producing systems with 100MHz buses
and RAM chips is a difficult and costly technological challenge-and a task
that few vendors will be up to at first. So the first systems out of the gate offer
fairly minor performance improvements over the existing 333MHz systems.
But about the time the 450MHz systems appear, you'll probably find
manufacturers geared up to take full advantage of the 100MHz bus, 2X AGP
and all the other benefits of the 440BX chipset. And that's when we expect
impressive performance gains.
That's not to say that early Deschutes adopters won't be offering some hot
machines in both desktop and mobile configurations. If you want to be the
first on your block at the keyboard of a fire-breathing 400MHz system, be
prepared to pay a premium. But prices are bound to tumble with the next
wave of Deschutes processors. |
