Both leading suppliers of microprocessors for x86 servers – Advanced Micro Devices and Intel Corp. – will reveal final specifications of their new high-end server chips code-named Istanbul and Beckton next week. While a lot of details are already known regarding the forthcoming Opteron and Xeon MP chips, there are some intrigues still here.
AMD Opteron “Istanbul”: Six Cores, Compatible with Existing Platforms, Unknown Clock-Speeds
AMD’s six-core Opteron processors code-named Istanbul feature 6MB of L3 cache, 3MB of L2 cache, dual-channel DDR2 memory controller and are compatible with socket F infrastructure. The only tangible improvement over the quad-core Shanghai processors that the Istanbul chips have (besides increased amount of cores) is HyperTransport Assist feature, which works the same way as Intel’s snoop filter inside high-end chipsets for Intel Xeon processors (keeps cache coherency traffic between the two sockets from appearing on the external bus).
AMD Opteron "Istanbul" die
Drop-in compatibility of Istanbul processors with existing infrastructure allows makers of current-generation servers to install higher-performance chips into existing machines and increase their performance-per-watt without any substantial investments into development. In fact, AMD will even provides discounts to those, who upgrades their existing servers to new processors, such as Opteron “Istanbul”
It should be noted that since Istanbul chips are still made using 45nm fabrication process, they will not be able to reach the same clock-speeds as quad-core chips. The main intrigue is how high the clock-speeds will be and what is the real-world performance benefit of six-cores. Currently, in fact, AMD promises 30% more performance in the same power envelope, hence, the clock-speeds of Istanbul are unlikely to be high, at least initially. Besides, it will be interesting to find out whether AMD also plans to offer processors with, for example, five cores made using Istanbul silicon.
AMD announced that it would start commercial shipments of its six-core Opteron chips in May and commercial systems will be available in June.
Intel Xeon “Beckton”: Eight Cores, Massive Cache, Mysterious Memory Controller
Although Intel unveiled the fact that it has plans for an octa-core processor back in 2007, the company did not reveal too lot of details regarding the chip to the general public. Nevertheless, discussions at various conferences reveal quite a lot of details about the forthcoming Nehalem EX chip for multi-processor servers.
The new enterprise Intel Xeon processor based on code-named Nehalem micro-architecture featuring 8-cores (16-threads due to HyperThreading support), 24MB of L3 cache, 2MB L2 cache, has 2.3 billion transistors and is made using 45nm process technology. The chip that is known under Beckton code-name will have four point-to-point quick path interconnect links to connect to other processors as well as system I/O operating at up to 6.4GT/s. The forthcoming Intel Xeon MP chip will also feature capability to disable certain cores or cache domains to improve manufacturing yields. The “cache and core recovery” technology will allow Intel to disable caches or cores independently in case they are defective. This will allow Intel to create processors not only with eight cores out of the Beckton dies, but also make chips with sever-core, six-core, five-core or any other amount of cores that makes sense. The processor will require a new platform with LGA-1567 sockets.
Intel Xeon "Beckton" die
One of the most intriguing parts about Intel Xeon “Beckton” is memory support. All Nehalem processors have integrated memory controllers, but the version for multi-processor machines will support four links for scalable memory interconnection with buffers. Since the details are now sketchy, it is not clear how Nehalem-EX’s memory controller works, but additional buffers are likely to enable denser memory configurations and support higher amounts of memory.
Intel's next-generation Xeon EX platform
Considering rather complex memory organization, eight cores, Hyper-Threading support and once promised compatibility with future Itanium processors of Xeon platform, a serious question is whether the forthcoming Xeon MP may actually start eating the cake of RISC and Itanium in the high-end mission-critical space.
But the main intrigue is when the new chips are set to ship. Recent confidential documents by Intel seen by X-bit labs did not contain any mentions of the octa-core chips designed for expandable enterprise-class systems due in 2009. Moreover, Intel also did not have plans to update the existing six-core Intel Xeon 7400-series family of processors with four or six processing engines this year, which means that eight-core Beckton will have to compete against twelve-core code-named Magny-Cours processor from AMD. But the plans are subject to change and if Intel releases the new Xeon EX in the coming months, AMD’s positions on the market will be rather weak.