Extra memory is essential for Intel's new Xeon E5 processors
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September 22, 2012
Intel's new Xeon E5 processors offer considerable power and speed, but if you want to get the most performance out of
them, particularly in virtualized server environments doing real transaction processing, you have to remember not to try
to cut corners on main memory.
Server memory optimization specialist Inphi, which has a vested interest in promoting load-reduced main memory (LRDIMM),
put an x86 server through its paces supporting a virtualized server stack running an online transaction processing workload
that simulates a busy online store to show just how much extra work you can get out of a server if you move to integrate LRDIMM
sticks instead of its RDIMM counterpart.
LRDIMM memory replaces the RAM stack register on a DDR3 memory module with a buffer chip that allows the memory chips on
the main module to run at higher clock speeds, which greatly boosts performance, in certain cases up to 45 percent.
The buffer chip also allows for more memory chips to be put on each channel, twice as many in fact, thereby increasing
the capacity even more.
The old and trusted adage that more RAM is your best friend in any computer or server system is still very alive and well,
and Inphi will tell you those fine words of advice when it comes to the performance of any system.
But to fully support LRDIMM memory, the on-chip memory controllers on a server CPU have to be tweaked, which is why you
can't just add it to any old server. For its part, Inphi makes the buffer chips used by Samsung, Hynix and Micron to craft
LRDIMM sticks, so it wants to demonstrate how good its solution is.
Intel's Xeon E5 processors support LRDIMM, and so do AMD's Opteron 6200 processors – so this is not an Intel-only topic,
and it's highly likely that future Power7+, Sparc T5, Itanium 9500 and even Sparc64-X processors will support LRDIMM sticks
in the near future.
In January of this year, when AMD was trumpetting its LRDIMM support with the Opteron 6200s, Inphi vice president of marketing
Paul Washkewicz said that a 1.35 volt LRDIMM with 32 GB of RAM will consume up to 20 percent less power than a 1.5 volt RDIMM with
16 GB of memory, something that needs to be taken into account by system admins.
To realize just how much of a performance boost and performance/watt advantage fat LRDIMMs offer over regular RDIMMs,
Inphi commissioned the server performance techs at Principled Technologies to run the DVD Store version 2.1 (DS2) benchmark
on a four-socket server to see what effect memory had on performance atop virtualized instances.
The DS2 2.1 test suite was announced in December 2011, and simulates and online music store with a Web front-end and a
MySQL database backend rubbing on Linux CentOS 6.3. You can
use Microsoft, Oracle, MySQL, and PostgreSQL databases and the front end has PHP web pages and C# drivers.
DS2 is already part of the VMmark 2.0 workload stack that VMware uses to test its hypervisor. In this particular instance,
Inphi and Principled Technologies loaded up VMware's ESXi 5.0 hypervisor on its servers and then ran multiple instances of the
DS2 test atop Windows Server 2008 R2 SP1 Enterprise Edition and Microsoft SQL Server 2012.
Each instance of the DS2 test had a 50 GB database. The DS2 virtualization benchmark was done on an IBM System x3750 M4
server sporting four E5-4650 processors running at 2.7 GHz, and 20 MB of L3 cache onboard and on the die.
The servers had four disks in a RAID 1 configuration to host the ESXi 5.0 hypervisor. The system was connected to two disk
SAS arrays through a controller in the box, and each array had two dozen 146 GB, 10K RPM disks, for a total disk capacity of
The test was run on a server with 10, 11, or 12 virtual machines, first with a unit using 384 GB of RAM based on 16 GB
RDIMM memory running at 1.33 GHz.
This is with 24 memory slots used, or half of the total slots in the system. Then the same tests were run with half the slots
filled with 32 GB LRDIMM memory sticks running at the same 1.33 GHz speed. Samsung was the memory supplier in both cases.
In other IT and server news
Microsoft has revealed additional details about the version of Office 2013 for ARM-powered devices running Windows RT,
including the fact that some customers will have to wait until January 2013 to get their hands on the final code.
Microsoft has explained that the version of Office Home & Student 2013 RT that will ship when Windows RT hits General Availability
status will indeed be only a preview version, as we previously reported.
The software behemoth further confirmed that all customers would eventually receive an upgrade to the final version of the
suite, but it added something we didn't know already-- that the upgrade will be delivered automatically via Windows Update at no
Exactly when customers will receive the update seems to depend mostly on their language. Microsoft says it will start shipping
the first updates in "early November", with subsequent updates for other languages rolling out through January.
The full schedule won't be announced until October 26, but presumably an English-language update will be among the early
But what we still don't know is exactly what "preview version" means when it comes to Office 2013 RT. It could simply mean
that the applications are buggy and crash-prone, or it could mean that the suite will ship with certain features disabled, or
even entire Office components missing.
But Microsoft did confirm something else we had suspected which is that even when the final version of Office 2013 RT ships,
it won't be 100 percent feature compatible with Office 2013 for desktop Windows.
For starters, it definitely won't ship with a version of Outlook. And in fact, Microsoft says "Windows RT does not support Outlook
or other desktop mail applications." The only way to check your email in the touch-centric OS will be to use a Windows Store
app, such as the mail app that comes bundled with Windows RT.
Source: Inphi Memory Virtualization.
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