MD has a 45nm six-core chip now just like Intel that will appear in HP, Cray, Dell, SGI, IBM and Sun systems this month. How the Istanbul chip and its adopters fare in a lousy make-do market remains to be seen.

AMD pushed the doohickey out Monday five months early in an effort to compete with the next Intel generation, the hyper-threaded quad-core Nehalem.

HE, SE and EE versions of the thing won’t be shipping until next quarter.

It’s eight months behind Intel’s six-core Dunnington Xeon, a hot little pre-Nehalem Penryn-style chip and the last Intel part with a front-side bus.

AMD says its new Istanbul chip offers 34% better performance-per-watt over Opteron’s previous quad-core Shanghai. Unlike Intel’s six-core, the part fits into the Shanghai platform so it takes little effort to incorporate and can pass for a value play.

It also uses DDR-2 memory rather than DDR-3, which makes it cheaper.

Istanbul is meant for two-, four- and eight-socket servers; that’s a possible 48 cores in a single chassis; Dunnington doesn’t accommodate two sockets and Nehalem is still limited to one and two sockets, which is why Intel trumpeted the eight-core Nehalem-EX last week.

Although the EX will support two, four and eight sockets it won’t be out until early next year when AMD expects to have its eight- to 12-core Magny-Cours chip ready.

The Six Core Opteron includes a bit of technology called HT Assist that uses part of the L3 cache like a look-up table so it can find data without asking each processor where it is, reducing processor-to-processor latency. It carries 6MB of L3 cache and 512KB of L2 cache per core.

AMD will be making the Istanbul at its spun-out fabs. It’ll come in speeds of 2.2GHz-2.6GHz and draw 75W on average. It runs from $455 to $2,649.