Original URL: https://www.theregister.com/2008/09/15/intel_dunnington_xeon/

Chipzilla unveils six-core 'Dunnington' Xeons

Edges AMD on big X64 iron

By Timothy Prickett Morgan

Posted in Channel, 15th September 2008 19:11 GMT

With virtualization and server consolidation bolstering sales of larger - and more profitable - servers, Intel wants to keep the competitive pressure on its rival in the X64 arena, Advanced Micro Devices, while also giving its server partners the chance to go after big RISC/Unix boxes in the same power class.

With the "Dunnington" six-core Xeon 7400 processors announced today, the X64 platform moves deeper into RISC territory and puts some water between Intel's offerings and those from AMD, which top out at four cores with the "Barcelona" Opteron 8300 series.

The Dunnington chip is socket-compatible with the existing "Tigerton" Xeon 7300 MP processor, and both are designed to be used in machines with four or more processor sockets. The Dunnington processor is based on the "Penryn" core that launched nearly a year ago, and the cores are implemented in a 45 nanometer, Hi-K process that allows the top-end chips to deliver as much as 50 percent more performance than the comparable 7300s while also consuming 10 percent less power.

The Dunnington Xeons use a 1.07 GHz front side bus and have 96 KB of L1 cache per core and 3 MB of L2 cache per core pair. The chip has 16 MB of shared L3 cache on the die - the first time the Xeon architecture has had L3 cache on the chip.

Like the other Xeons since the "Woodcrest" dual-core Xeons from several years ago, the Dunningtons have support for a virtualization feature called VT FlexMigration, which ensures that virtual machine hypervisors and their teleportation features (which allow VMs to be moved around a network of machines) are both forward and backward compatible.

The chip does not, like its Tigerton predecessor, have HyperThreading, which presents two virtual instruction streams to an operating system for every real one on the chip. HyperThreading tends to boost performance by about 20 to 30 percent in the X64 architecture, but it also eats up die space.

The Dunnington chip has 1.9 billion transistors, making it one of the largest chips Intel has ever made in terms of transistor count - second only perhaps to the "Tukwila" quad-core Itanium, which is expected to come in at just over 2 billion transistors.

Depending on how little money you have, Intel turns off cores and cache until you meet your budget. Well, sort of. The top-end X7640 has all six cores activated, runs at 2.66 GHz, and has 16 MB of L3 cache; it has a 130 watt thermal design point (TDP) and costs $2,729 in 1,000-unit quantities. (All Intel processor prices are per chip if you buy a 1,000 chip tray all at once.) The practical Dunnington for most users, given budget and thermal constraints, is probably the E7450, which also has all six cores running, but only 12 MB of L3 cache and a clock speed of only 2.4 GHz, which drops the thermals down to 90 watts and the price down to $2,301.

The only other six-core Dunnington is a low-voltage variant, the L7455, which runs at 2.13 GHz and has 12 MB of L3 cache and sports a 65 watt TDP. It costs $2,729, just like the faster 130 watt part, which means if you want the best performance or the best thermals, you pay either way.

The E7440 is the fastest quad-core variant of Dunnington, which runs at 2.4 GHz and has 16 MB of L3 cache at a price of $1,980, and cutting the cache back to 12 MB and reducing clock speed on a quad to 2.13 GHz drops the price further on the E7430 to $1,391. The E7420 runs at 2.13 GHz as well, but has only 8 MB of cache and a price of $1,177.

All three of these four-core Dunningtons have a 90 watt TDP. The remaining Dunnington is a low-voltage L7445 part, which has four cores active, running at 2.13 GHz and accessing a 12 MB L3 cache. It costs $1,980.

Tom Kilroy, general manager of Intel's Digital Enterprise Group, said at the Dunnington launch in San Francisco that the number of virtualized servers out there in the data centers of the world has grown by 50 percent in the past year, and that server consolidation is a big driver behind sales of the kinds of big boxes that chips such as the Xeon 7400 series engender. Of course, needing to run massive ERP suites and their related databases, or huge email servers, also drives sales of big iron.

According to benchmark data presented across a number of different workloads by Kilroy, the 7400s in four-socket configurations using six cores best the 7300s using quad cores by between 14 and 48 percent. The weakest performance improvement is on e-commerce workloads, with the average being somewhere close to 35 percent. The best performance Intel showed for the Dunnington chip compared to its predecessor was for database processing as it relates to the relatively new TPC-E benchmark test. On the TPC-C test, the performance boost was only 43 percent.

Kilroy said that in the past year, since Intel has started shipping 45 nanometer processors, the company has shipped close to 50 million units using the chip making technology. ®