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Intel's 'Tukwila' Itaniums - hot n' pricey
How much for an upgrade?
Analysis As El Reg duly reported earlier today, Intel took the wraps off its
long awaited and many times tweaked "Tukwila" quad-core Itanium 9300
processors for midrange and high-end servers. But let's take a look at the
feeds and speeds of the chip itself and how the lineup compared to the prior
Itanium 9100 series.
There are five variants of the Itanium 9300 series, compared to seven in the
prior 9100 series. The chips as delivered were basically the same as what
people were whispering about for the past year.
What we knew for sure about Tukwila was that it would have four cores, two
threads per core with HyperThreading, 6 MB of L3 cache per core (for a total
of 24 MB), integrated DDR3 main memory controllers - all implemented in a
fairly ancient 65 nanometer process with some 2 billion transistors. Tukwila's
clock speeds were expected to be in the range of 1.2 GHz to 2 GHz, with topend
parts burning at 170 watts, and performance was hinted to be about
twice that of the dual-core Itanium 9100s.
Here are their basic feeds and speeds of the Itanium 9300s announced
today, including the single unit price when OEMs buy them at list price in
1,000-unit quantities:
As you might expect, Intel is trying to hold its price points even as it uses
Moore's Law to double up the cores and add threads to the Itanium
processor. In fact, each new Itanium 9300 processor costs a little bit more
than the Itanium 9100 processor it replaces in the lineup. The modest price
increase is generous compared to the prior product line, and with the chips
being binary compatible with other Itaniums, moving operating systems and
applications to the new chips is not an issue.
(Wringing the full amount of performance out of any new chip does often
require recompilation and other tweaking, however, and the Itanium 9300,
with its radically different chipset and QuickPath Interconnect, will be no
different in this regard).
The Tukwilas will give customers running HP-UX, Windows, Linux, OpenVMS,
and NonStop operating systems more threads, more cache, and slightly
higher clock speeds in a few cases. But the 800 per cent increase in
interconnect bandwidth, 500 per cent more memory bandwidth, and 700 per
cent increase in main memory capacity using 16 GB DDR3 DIMMs will
presumably make customers not mind a slight price rise on raw chips to get
around twice the throughput.
What's the upgrade cost?
The issue is really what server makers will charge for upgrades for system
boards using the Tukwila chips - if they even make upgrades possible,
considering the changes in processor sockets, memory, and interconnect in
making the jump from the prior dual-core "Montecito" Itanium 9000s and
"Montvale" Itanium 9100s to the Tukwila Itanium 9300s.
Intel did not, by the way, cut the prices on these older Itanium chips in half,
so customers who want better bang for the buck on their Itanium systems
have to move forward.
The Itanium 9300 chips also sport better power management and the
quiescing of cores inside the chip, which allows other cores in the Itanium
9300 to be slightly overclocked - what Intel calls Turbo Boost, a feature that
is available in some of its Xeon family of server chips. The Turbo Boost is
fairly modest, with a 7.5 to 9.8 per cent clock bump on the four-core
versions of the Itanium 9300. The dual-core version of the chip, the Itanium
9310, doesn't have Turbo Boost at all and has its on-chip L3 cache cut down
to 10 MB (5 MB per core).
This chip costs $946, and it will no doubt be used by Hewlett-Packard in
blade servers where thermals are an issue. At 130 watts, it is going to be
tough to put two of these Itanium 9310s on a single blade, and it would
seem to be impossible to cram two of the Itanium 9340 (1.6 GHz) or 9350
(1.73 GHz) chips onto a blade, considering that each chip dissipates 185
watts.
That said, the performance per watt on the Tukwilas should be a little better
than with the dual-core Montvales. The top-end Itanium 9150N had 24 MB of
L3 cache for its two cores and burned 104 watts running at 1.66 GHz and 1.6
GHz. Depending on how clock speeds translate into performance and how
you compare different Montvale and Tukwila chips at the high end of the line,
this works out to a 10 to 15 per cent improvement in performance per watt.
Still, it is hard for Itanium to compete in terms of bang for the buck with the
Nehalem and Westmere family of Xeon processors, the former announced
last March and the latter due this March. The current X5570 has four cores
running at 2.93 GHz (with eight threads), 8 MB of L2 cache on chip (no L3
cache), a 95 watt thermal envelope, and costs $1,386 each when bought in
1,000-unit quantities.
The one interesting thing that Intel has not talked about is what happens to
performance on the Tukwilas with applications that are sensitive to L3 cache
memory(like database transaction processing, for instance). When you
compare roughly like-for-like Tukwila and Montvale chips, you have about
the same cache memory in the SKUs, but Tukwila has half the cache memory
per core.
This may have been the real reason that Intel pushed out Tukwila to graft on
the buffered memory architecture - called the Scalable Memory Buffer) that
is coming out later this quarter with the eight-core "Beckton" Nehalem-EX
processors and is now part of the Itanium 9300 design. That buffered
memory sits between standard DDR3 DIMMs and the memory controller on
either the Itanium or Nehalem-EX chips. It actually sits on memory cards,
apparently, that plug into the system boards. This memory buffering helps
the Itanium 9300s to support 1 TB of main memory on a four-socket server,
and presumably, it makes up for the smaller L3 cache memories.
By comparison, IBM's just announced Power7 chip can support only 512 GB
across four sockets. But that Power 750 machine announced today also has
32 cores in those four sockets, with 128 threads, compared to the Tukwila's
16 cores and 32 threads. IBM's cores are also clocking in at roughly twice the
clock speed too. (Although you have to be careful about comparing clocks
across chip architectures).
It will be interesting to see how the performance of these two midrange
boxes stack up to each other and to Nehalem-EX and systems based on
Advanced Micro Devices' "Magny-Cours" twelve-core processors. The foursocket
market is going to get very competitive - and very quickly. ®

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