Dunnington materializes as six-core Xeon 7400

— 2:19 PM on September 15, 2008

As the "core wars" continue to rage on, Intel has indulged itself in a little diversion. The chipmaker's new Xeon 7400 server processor packs a massive, 1.9-billion-transistor die, but it feature six cores and devotes a good chunk of its die area to a huge, 16MB pool of shared L3 cache.

Why six cores instead of eight? Intel's Pat Gelsinger answered that question back in March, when he mentioned that Intel wanted to balance cores with L3 cache, and a "detailed set of workload characterizations" had led it to conclude that six cores with 16MB is the "sweet spot." The launch press release says Xeon 7400 CPUs can improve performance by almost 50% in systems that make heavy use of virtualization, databases, and other "data demanding workloads."

Despite its monstrous transistor count, Dunnington isn't so different from other Core 2 and Xeon CPUs. Intel used its 45nm Penryn core as a building block, outfitting the new Xeon chip with three dual-core groups and filling up the rest with cache and interface logic. Core clock speeds range up to 2.66GHz, while Intel stuck with 1066MHz on the front-side bus. Dunnington's most surprising attribute may well be its power envelopes, since even the fastest of these six-core monsters only draws up to 130W. You can get low-voltage, six-core derivatives with power envelopes as low as 65W, too. Check out the Xeon 7400 lineup below:

Processor Cores Speed L3 cache TDP
Xeon X7460 6 2.66GHz 16MB 130W
Xeon E7450 6 2.40GHz 12MB 90W
Xeon E7440 4 2.40GHz 16MB 90W
Xeon E7430 4 2.13GHz 12MB 90W
Xeon E7420 4 2.13GHz 8MB 90W
Xeon L7455 6 2.13GHz 12MB 65W
Xeon L7445 4 2.13GHz 12MB 50W

Owners of existing server farms should be glad to know that Intel designed Dunnington with backward-compatibility in mind. Xeon 7400 CPUs fit in the same Caneland platforms as older quad-core/four-socket Xeon 7300s, so they're little more than drop-in upgrades in some cases. Server makers should be able to fit as many as 16 Xeons 7400s in a single system, for a total of 96 processing cores with as much as 256GB of memory—impressive credentials for any server.

According to Intel, you can look forward to Xeon 7400-based systems from the likes of Dell, Egenera, Fujitsu, Fujitsu-Siemens, Hitachi, HP, IBM, NEC, Sun, Supermicro, Unisys. Among those, IBM, NEC, and Unisys are cooking up servers that can scale to 16 sockets. Individual Xeon 7400 chips cost $856 to $2,729 a pop in 1,000-unit quantities.

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