AMD today announced availability of the world’s first six-core server processor with Direct Connect Architecture for two-, four- and eight-socket servers. Six-Core AMD Opteron™ processors (code-named “Istanbul”) extend AMD’s commitment to offering server customers superior value at every price point with unmatched platform flexibility.
Across a single platform, AMD can address the need for more cores and greater scalability with the new Six-Core AMD Opteron processor and offer a cost- and power-efficient solution with Quad-Core AMD Opteron processors. Systems based on Six-Core AMD Opteron processors are expected to be available beginning this month from leading OEMs including Cray, Dell, HP, IBM and Sun Microsystems, along with support from motherboard and infrastructure partners. HE, SE and EE versions of the Six-Core AMD Opteron processor are planned for the second half of 2009.
The most notable change of Istanbul is the addition of a feature AMD calls HT Assist. HT Assist is essentially a probe filter intended to reduce the overhead required for the synchronization of cached data across CPUs in multiple sockets. HT Assist reserves space in each processor's L3 cache, in which it stores an index of where that CPU's cache lines are being used system-wide. The CPU then becomes "host" of the cache lines stored in its directory. If any CPU needs an update about a particular cache line, it will often know which CPU is the correct host to probe for that information. AMD says HT Assist can replace broadcast probe requests (sent to all sockets) with directed requests in 8 of 11 typical CPU-to-CPU transactions. This reduction in probe traffic can yield big gains in available system bandwidth, whose Stream bandwidth increased from roughly 25GB/s to 42GB/s with the addition of Istanbul processors with HT Assist.