Just a few. months ago we reviewed the Harpertown processor. This processor was launched just after e launch of 45 nm Penryn based Xeon 5400 series model. This time we had the opportunity to test the next in line from Intel: Dunnington processor. The server we received had 4 distinct processors with 6 cores each. As there are not many applications that use all available cores. this processor is meant for very high end computing and for virtualization in large enterprises. It can also be used in cloud computing or rack optimized and ultra-dense SKUs.

Technology in Dunnington

To understand and appreciate the tech used in Dunnington. we'll start with a bit of history of the previous generation server processors. The Xeon 5200 series codenamed Woodcrest. based on the In¬tel's core-micro architecture was the server and workstation version of the [n¬tel Core 2 processor. The fastest processor in this category operated at 3.0 GHz. claiming better performance and also less energy consumption than previous processors. In Jan 2007, Intel launched its quad-core. Core2quad, as the 3200 se¬ries which comprised of two separate dual core dies placed next to each other in one CPU package. This was targeted at blade servers. The 3300 series was simi¬lar to 3200 series but was manufactured using 45 nm process and featured XD bit and virtualization technology.

True to Intel's tick-tock release cycle of processors, where tick means a refresh of the current architecture and tock means a brand new architecture. the clock ticked and the Harpertown Xeons were released in late 2007. This family of processors consisted of dual-die Quad¬core processors manufactured on a 45 nm process and featured 13 3 3 to 1600 MHzfrontside bus withlesserTDPs, rated between SOW to 150W depending upon the model.

And now Intel has become the first in the x86 processor market to launch a processor with six cores. Their offering before this was the 7300 series, code named Tigerton and consisted of two dual core architecture silicon chips on a single ceramic module. Boasting of greater processing capabilities. the Tiger¬ton was based on Intel's Caneland (Clarksboro) platform. But now the Dun¬nington, or the 7400 series. features single-die six core design and is based on Intel's 45 nm Penryn processor. Like the Harpertown Xeon processor it has three dual cores clubbed together.

Compared to its predecessor, this processor has signifi¬cantly more cache, ie 16 MB L3 cache which is shared among all six cores, 3 MB L2 cache which is shared among two cores and 9 6 KB L1 cache, The increase in the size of cache will lead to improvement of performance, mainly by reducing the latency in accessing frequen tly used data. However, the processor speed remains ap¬proximately the same, ranging from 2.13 to 2.66 MHz. However. the FSB of Dun¬nington (1066 MHz) compared to Harpertown which has 1600 MHz (re¬viewed in J an 2008) is much lower, which can be a bottleneck but the 3 MB cache size is said to reduce this to great extent. One good thing is that if you already have a Tigerton's nPGA604 socket, then you just have to plug this CPU into that. And it is compatible with Caneland chipsets too.

This 7400 series processor also sup¬ports VT-x technology, ie Intel Flex mi¬gration and Flex priority technology. Earlier successful live virtual machine migration was dependent upon the com¬patibility of the two CPUs between which

the migration is being done. And also to ensure that the VM is stable after the mi¬gration is done. All these issues have been taken care of with the new Intel Flex mi¬gration technology. Now this also solves the requirement of buying a compatible resource pool across multiple generations of Xeon processors. This gives you the op¬tion of choosing the right server platform with respect to performance, cost and power for your enterprise. Flex Priority is another such hardware feature which helps in optimizing virtualization by im¬proving virtual machine access to the task priority register.