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An document consistent with Intel roadmaps details the company's upcoming 6-core processor

The same slide deck details side-by-side projections of Nehalem with other AMD and Intel processors

George Out estimates the floating point point and integer performance by extrapolating datapoints on the slid  (Source: ZDNet)
Sun confirms what Intel has been dying to tell us, at least off the record

Late last month in Austria, Intel presented Sun with roadmaps discussing details of its upcoming server platforms, including the fairly secret Xeon Dunnington and Nehalem architectures. Unfortunately for some, this presentation ended up on Sun's public web server over the weekend.

Dunnington, Intel's 45nm six-core Xeon processor from the Penryn family, will succeed the Xeon Tigerton processor.  Whereas Tigerton is essentially two 65nm Core 2 Duo processors fused on one package, Dunnington will be Intel's first Core 2 Duo processor with three dual-core banks. 

Dunnington includes 16MB of L3 cache shared by all six processors. Each pair of cores can also access 3MB of local L2 cache.  The end result is a design very similar to the AMD Barcelona quad-core processor; however, each Barcelona core contains 512KB L2 cache, whereas Dunnington cores share L2 cache in pairs.

To sweeten the deal, all Dunnington processors will be pin-compatible with Intel Tigerton processors, and work with the existing Clarksboro chipset.  Intel's slide claims this processor will launch in the second half of 2008 -- a figure consistent with previous roadmaps from the company.

The leaked slide deck also includes more information about Intel's Penryn successor, codenamed NehalemNehalem is everything Penryn is -- 45nm, SSE4, quad-core -- and then some.  For starters, Intel will abandon the front-side bus model in favor of QuickPath Interconnect; a serial bus similar to HyperTransport.

Perhaps the most ambitious aspect of Nehalem? For the first time in 18 years Intel will pair its processors cores up with on-die memory controllers.  AMD made the switch to on-die memory controllers in 2003. For the next three years its processors were almost unmatched by Intel's offerings.  The on-die memory controller can't come a moment too soon. Intel will also roll out tri-channel DDR3 with the Nehalem, and all that extra bandwidth can only be put to use if there are no bottlenecks.

As noted by ZDNet blogger George Ou, the slides contain some rudimentry benchmarks for Nehalem and other publicly available processors.  From this slide deck, Ou estimates Nehalem's SPEC*fp_rate_base2006 at 163 and the SPEC*int_rate_base2006 at 176.  By contrast, Intel's fastest Harpertown Xeon X5482 pulls a measly 80 and 122 SPEC fp and int rate_base2006.

The Nehalem processor more than doubles the floating point performance of its current Penryn-family processors.  Ou adds, "We’ll most likely know by the end of this year what the actual scores are, but I doubt they will be more than 5% to 10% off from these estimated projections."

It's important to note that these estimates are not actual benchmarks.  Intel's document states, "Projections based on *SPECcpu2006 using dual socket Intel Xeon 5160 Processor performance as the baseline." As discussed on DailyTech before, simulated benchmarks offer little substance in favor of the real deal.

As of February 2008, the company plans to launch Nehalem in Q4 2008.

Sun has since removed the slide deck from its website.


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By Anonymous Freak on 2/25/2008 4:22:22 PM , Rating: 2
Before AMD's Opteron and Athlon 64 line, all of Intel and AMD's processors used what we consider a 'conventional front side bus' to a Northbridge chip. This Northbridge chip contains the memory controller, and acts as 'traffic cop' for all memory accesses from any device, including the main CPU.

Because this chip is physically separate, and the CPU has to talk to it through a certain speed front side bus, it adds latency to memory access, and in some cases, the front side bus even bottlenecks memory access. (On Intel's laptop chipsets, the 800 MT/s front side bus is capable of only 6.4 GB/s, while the dual-channel 667 MT/s memory controller can supply 10.6 GB/s. This means that there are potentially times when the processor is 'starved' for bandwidth, even though the memory controller could supply it.

An onboard memory controller takes away latency, and removes any bottlenecks other than the raw memory bandwidth bottlenecks. (So, for example, dual-channel 1600 MT/s DDR-3 will be able to be fully utilized.) Early on when AMD implemented an on-die memory controller, they had a MAJOR memory bandwidth advantage over Intel, and has retained, until VERY recently, a major latency advantage. However, in Intel's x3x-series chipsets (G33, P35, X38, etc.,) Intel has improved caching so that the latency advantage has all but disappeared. And Intel's embrace of newer memory technologies faster than AMD (DDR-2, and now DDR-3,) have increased bandwidth, as well.

Now, if Intel sees the same benefits from their current memory performance that AMD did when they moved to onboard memory controllers, Intel will dominate all memory benchmarks by a VERY wide margin. I also wonder if the onboard FB controller on the Xeon series will negate most of FB's shortcomings (massive latency,) and make it truly competitive with modern non-FB memory?


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