The Unix Guardian--Core Transition Complete as Intel Ships 'Tigerton' Xeon MPs

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Volume 4, Number 32 -- September 6, 2007

Core Transition Complete as Intel Ships 'Tigerton' Xeon MPs

Published: September 6, 2007

by Timothy Prickett Morgan

At long last, chip maker Intel's transition from the NetBurst architecture embodied in its Pentium 4 and related Xeon DP and Xeon MP processors for servers to the new Core microarchitecture that debuted nearly two years ago is complete. Yeterday, Intel launched the quad-core "Tigerton" Xeon 7300 series processors, which are geared to midrange and high-end servers and which give the high-end Xeon line the kind of performance, price/performance, and performance per watt that Intel needs to compete well against alternatives from Advanced Micro Devices.

The launch of the Tigerton Xeon MPs coincides with the new "Clarksboro" 7300 chipset from Intel, which includes various improvements in I/O and caching structures to provide balanced performance in the quad-core chip. Like Intel's "Clovertown" Xeon 5300 chip, the Tigerton chip is really two dual-core Core architecture chips placed side-by-side and sharing a single chip package. The Xeon 5300s are aimed at servers with two CPU sockets (eight cores per machine), while the Xeon 7300s are aimed at machines with four CPU sockets (16 cores per machine). As has been the case for a number of years, the Xeon MP architecture allows multiple four-socket system boards to be lashed together to create even more scalable SMP configurations. The largest Xeon MP systems support up to 32 sockets in a single system image, and that has not changed with the Tigerton Xeon 7300 launch.

The launch of the Tigerton Xeon 7300s puts the dual-core "Tulsa" Xeon 7100s out to pasture. The Tulsa chips made their debut last August and are based on the "Paxville" Xeon DP core, and put two of these into a single package to double up the cores. The Tulsa chips had a thermal design point (TDP) of 95 watts or 150 watts, with electricity consumption and heat dissipation varying depending on clock speed and cache sizes. The Tigerton chips use the new Core architecture, and the chips inside the package are essentially variants of the true dual-core "Woodcrest" Xeon 5100 processor that is also used in the Clovertowns. The eight Tigerton chips have TDPs ranging from 50 watts to 80 watts to 130 watts.

The Tigerton launch was timed to give Advanced Micro Devices heartburn just before it launches its "Barcelona" Opterons on Monday. The Barcelona chip is a true quad-core--meaning it puts four cores, their caches, and their memory controllers--on a single die. The Barcelona chips were expected in mid-year, and if they were timed to the market demands, they would have been here at the end of last year. Quad-core processors--whether they are true or quasi quads--offer substantial power efficiency and throughput performance improvements, and that is why, according to Diane Bryant, vice president and general manager of Intel's Server Platforms Group, the company has sold "millions" of quad-core chips since the end of last year. By the way, she says that the Intel plan was to only have sold 1 million quad-core Xeons by mid-2007, so Intel. "We are way beyond where we hoped to be," she says.

Bet that stings, don't it, AMD?

Roughly speaking, the Xeon 7300s will offer from 70 percent to 100 percent the performance of the Xeon 7100s they replace. Applications that like threads do better, of course, and transaction processing workloads, which have a little more trouble scaling on multicore architectures, are at the low end of that performance range. The main Xeon 7300 chips have an 80-watt TDP, the same as the Woodcrest and Clovertown Xeon chips for two-socket machines; this is a lot lower than the 150-watt parts that they replace, and it means that blade server vendors such as IBM, Hewlett-Packard, Sun Microsystems, and Egenera can cram very powerful four-socket blade servers into their chassis and not worry about melting something. Intel is also delivering a low-voltage, 50-watt variant of the Tigerton chip, and for customers who need more clock speed for single-threaded applications, there are also two dual-core variants with one core per side of the chip de-activated and a higher clock speed. For the top-end Tigerton parts, Intel is delivering a factor of three improvement in performance per watt.

In terms of performance, the top-end Tigerton part is the X7350, which clocks at 2.93 GHz and which includes 8 MB of on-chip L2 cache; this part is rated at 130 watts and costs $2,301. There are four quad-core, 80-watt Tigerton parts. The E7340 runs at 2.4 GHz, has 8 MB of cache, and costs $1,980; the E7330 runs at 2.4 GHz, has 6 MB of cache, and costs $1,391; the E7320 runs at 2.13 GHz, has 4 MB of cache, and costs $1,177l and the E7310 runs at 1.6 GHz, has 4 MB of cache and costs $856. The two dual-core Tigertons have 8 MB caches, have an 80-watt TDP, and run at 2.93 GHz or 2.4 GHz, respectively, and are known as the E7220 and the E7210. These chips cost the same $1,177 and $856 as the two slowest quad-core parts. The X7345 has a 50-watt TDP, and runs at 1.86 GHz and comes with an 8 MB cache. The interesting thing about those prices is that they are exactly the same as the equivalent Xeon 7100 processors from last year. Intel is doubling up the cores for the same dough. (All of those prices were for the usual 1,000-unit quantities.)

Intel's OEM customers have been getting Tigerton parts and Clarksboro chipsets since June, and according to Bryant many are ready to start shipping products now or will be able to do so shortly. Over 50 server makers are working to get Tigerton boxes out the door, and they are doing so because the thermal capacities, core counts, and memory extensions of the Tigerton chips allow more physical servers to be consolidated onto big X64 boxes using server virtualization hypervisors.

The Tigerton chips are not just about cramming more cores into the same space, says Bryant. For one thing, the Tigerton chip and related Clarksboro chipset supports up to 256 GB of main memory in a four socket system. Intel doubled the number of memory DIMMs supported and moved to 8 GB DIMMs to accomplish this. But it won't be long before 4 GB DIMMs are reasonably priced, which means customers can doubled up on core counts in a box and double up on memory for essentially the same money they would have paid a year ago. This is a requirement for server virtualization and consolidation. Virtualized machines need a lot more memory than workloads running on separate physical servers require.

The Tigertons, which are based on a 65 nanometer process, use a new socket (one that will also be used by the future "Dunnington" kickers in the Xeon MP family, which will use 45 nanometer processes and which will probably be based on the "Penryn" cores due later this year). These new sockets have a new bus architecture called Dedicated High Speed Interconnect, replacing the front side bus used with Xeons for years. Each CPU on the board now has its own link to I/O rather than sharing it through front side buses, and the 7300 chipset has a 64 MB snoop filter that sits between the processors and main memory to reduce latencies in moving data from main memory banks into the right processor core in the complex. Memory capacity is up by a factor of 4 times and memory bandwidth has doubled with the 7300 chipset, which means those extra cores will get used by workloads.

The Tigerton chips and related 7300 series chipset also includes a feature called VT FlexMigration, which is similar to an AMD feature announced last week called AMD-V Extended Migration. The idea behind these features is to allow server virtualization hypervisors to mask the differences in past, current, and future processors and allow virtual machine guests and their operating systems to move around a mix of servers using different processor technologies. Basically, these features adhere to a lowest common denominator to create a common pool of hardware resources, thereby ensuring compatibility.