Quote Originally Posted by Macadamia View Post
http://www.techreport.com/articles.x/16448

HT assist seems to be something nifty. Plus HT3.0 will suffice for 12 cores and help 24 thread scaling.

For a drop-in upgrade to Socket F it seems wicked nice. It won't win SAP SD benchmarks because it's not quad-channel DDR3 at work yet, but for HPC and Virtualization it should definitely give some sense to a certain CPU called Gainestown.


(And no, Gulftown was not on demo at IDF. It should not catch Q3 or Q4 of 2009, probably Q2 2010 for servers. Magny probably comes 1 quarter later with QC DDR3.)
Wicked demo,thanks for posting the news Macadamia .

24 cores in task manager

What is more interesting is the perf. scaling. 1.68x more performance in Stream benchmark for 1.5x more cores that all the chances are were working at lower clocks in Istanbul's case.
Probable reason: "HT Assist"
Part of the answer, it seems, may be a feature new to Istanbul that AMD calls HT assist (presumably for HyperTransport assist). This feature is what the company calls a probe filter (and may more commonly be called a snoop filter) that functions to reduce traffic on socket-to-socket HyperTransport links by storing an index of all caches and preventing unnecessary coherency synchronization requests. Current Opteron systems use a broadcast-based probe protocol, sending probe requests to all sockets. Istanbul, instead, either knows that no probes are required or is able to do a directed probe to a single socket. (Although it may still use broadcasts in certain, specific situations.) Istanbul's probe filter stores its data in the processor's L3 cache. The amount of cache space dedicated to probe filter storage, AMD says, will be configurable in the BIOS, and the more space dedicated to probe filter storage, the more granular its operation will be.
Comment on validation of six core parts:
Beyond that, AMD expects system vendors to treat Istanbul very much like any other new Opteron speed grade, with a much easier qualification path than an all-new product. That should mean fairly quick and widespread adoption of six-core Opterons among vendors shipping Shanghai-based systems today, if all goes as planned.
The Istanbul core obviously taped out some time ago,probably Q3 2008.Being souped-up and upgraded Shanghai,AMD should have no problems launching the parts in Q3.