Harpertown: New 45nm Xeons from Intel
Posted on: 09/17/2007 05:00 AM

It's been quite a while now since Intel introduced their Bensley platform for workstations and servers. As a platform, Bensley brought all sorts of new features to the table. Things like faster, independant front side busses for the processors, dedicated quad-channel memory bus, and support for FB-DIMMs were the major additions that come immediately to mind. Bensley originally consisted of two different chipsets, the 5000P (Blackford) for servers and the 5000X (Greencreek) for workstations. The notable difference was the presence of the snoop filter in the 5000X chipset, a feature that was great for workstation applications, but not so great for servers.

The first Bensley platform I looked at arrived with a pair of Dempsey based Xeons. Dempsey was the last of the Netburst based Xeons, and while they were decent performers at the time, they drank electricity like water, and radiated enough heat to warm a small house. The real beauty of Bensley wasn't fully realized until later when Intel released their Core 2 based Woodcrest Xeons. Woodcrest hit the scene and turned Xeon performance on its ear. They ran fast and stayed cool, qualities not seen in the Xeon world for quite a while. Considering Intel's transition to dual-core consisted of putting two single-core dice into one package, and considering the immediate popularity of Woodcrest, it seemed only a matter of time before the market would see its first quad-core processor.

Clovertown, a 65nm quad-core Xeon, launched in November of last year and as expected, it is basically a pair of Woodcrest dies in a single package. Each core in the package has a dedicated 4mb of L2 cache, and runs on a 1066 MT/s or 1333 MT/s front side bus. These days Clovertown has matured a bit and is available in 50w, 80w and 120w TDP flavors, and in speeds up to 2.66ghz. Clovertown performance is about what you would expect from (basically) two pairs of Woodcrest processors. Unfortunately, Clovertown started pushing the limits of the Bensley platform, especially in the memory bandwidth department.

That brings us to today...

Today marks the launch of Intel's new, improved Xeons, codenamed Harpertown. Harpertown is a member of the Penryn family. Penryn is a multi-core processor based on an industry leading 45nm manufacturing process. A die-shrink really is a wonderful thing. It allows the chip designers to do all sorts of neat things to their processors. They can lower the voltage (indirectly decreasing power consumption and subsequently generated heat), add cache, tweak the pipelines, or, in the case of Penryn, all of the above.

While Harpertown is the star of our show today, it is not without its supporting players. Along with the new processors, Intel is also releasing a new platform to support those processors, codenamed Stoakley. The Stoakley platform is composed of the aforementioned Harpertown and (its dual-core sibling) Wolfdale processors, and the new Seaburg (Intel 5400) chipset.

Die-shrinks do great things for processors, but they are equally effective for chipsets. Seaburg is basically a shrunken Blackford/Greencreek chipset with a few added features. Chipset power consumption (and heat) are down due to the die shrink, and that allows a little more headroom for faster front side busses (up to 1600 MT/s from 1333 MT/s for Blackford/Greencreek). It is also important to note that there is only a single chipset for the Stoakley platform, and it includes the snoop filter. Intel engineers were able to tweak the snoop filter this time around, so it is there to boost workstation performance without negatively impacting server performance.

I think I've rambled enough, and I know everyone is anxious to see the performance data. I'll leave the nitty-gritty technical and architectural details to Dave over at Real World Tech. He'll do a much better job of explaining all the nuances of each improvement than I ever could. So, why don't we move on to the test system details and get this show on the road!

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