AMD has introduced a six-core version of its Opteron server chip designed for the most demanding datacentre workloads, such as databases and server consolidation using virtualisation.
Codenamed Istanbul, the six-core chip is available immediately, several months earlier than had been planned. It is expected to appear in four-socket systems from Dell, HP, IBM and Sun in the near future.
Istanbul delivers up to 34 per cent higher performance than last year's Shanghai quad-core chip running at the same clock speed, according to AMD. It fits within the same power envelope as Shanghai, and even uses the same socket infrastructure so that existing systems can be upgraded.
"Six cores will deliver even more performance per dollar. More performance, but within the same power envelope," said Pat Patla, vice president of AMD's Workstation and Server division.
Patla said that AMD's strategy is to focus more on "usage-based scenarios". As part of this, the company sees Istanbul being used for high-end workloads requiring performance and greater scalability, while the quad-core chips are now positioned for cloud computing and dense environments where energy efficiency is paramount.
"Virtualisation and maximum utilisation are driving the need for more cores. We feel that six addresses that need well," Patla added.
One new feature introduced in Istanbul is HT Assist, designed to improve the efficiency of the HyperTransport interconnect by cutting the volume of 'probe traffic' between chips in a multi-socket system. It sets aside some of each chip's L3 cache to act as a directory, tracking whether information it needs is already in the cache of another processor and can be fetched more speedily than by going out to memory
"The CPU knows exactly which [other] processor to go to for the information it needs instead of sending out broadcast requests, making for more efficient memory access," explained Patla.
One vendor promising to have Istanbul-based systems in the near future is HP. Paul Gottsegen, marketing vice president for enterprise servers at the firm, said the new chip will appear in servers and workstations such as the firm's xw9400 system.
"You'll see us very quickly deploy six-core across our entire G6 ProLiant line, and in all form factors - blade, rack and tower," Gottsegen said.
To put Istanbul in perspective, Patla said the new chip offers 14 times the performance of AMD's first single-core Opteron introduced in 2003. A datacentre with 314 systems based on that original chip could now be replaced with just 21 servers based on Istanbul, representing a 95 per cent saving on power consumption for the same performance level, according to AMD.
"Or you could do a one-for-one upgrade for a huge boost in performance and still save up to 30 per cent on your annual energy costs," he claimed.
In a dig at rival chip maker Intel, Patla said that Istanbul is "the only six-core processor available today with Direct Connect architecture", referring to the Opteron family's on-chip memory controller and high-speed HyperTransport interconnect between chips.
Intel already has a six-core processor, the Xeon 7400, but this uses a single shared bus for all memory access. The newer Nehalem chips use a similar architecture to the Opteron, but currently available versions have a maximum of four cores. Nehalem EX will have up to eight, but is not expected to appear in shipping systems until 2010.
Istanbul is available initially at clock speeds of 2.6GHz, 2.4GHz and 2.2GHz in AMD's standard 75W thermal rating. Further clock speeds are likely to come before the end of this year, along with SE (105W), HE (55W) and EE (40W) versions.
A forthcoming AMD platform with up to a dozen cores codenamed Magny-Cours is still scheduled to appear in 2010.