AMD HAS RESHUFFLED its roadmap and inserted a new product line in the middle. The new chips are six-core variants of Shangahi.

You all know about Barcelona, and it is followed up by Shanghai, the 45nm shrink in Q4. It brings a 6M L3 and cHT-3 to the table with a bunch of minor tweaks. The official line is a 20 per cent clock-for-clock speed improvement over Barcelona. In the same timeline, Montreal, the eight-core two-die part has shuffled off this mortal coil.

The new stuff starts a year later with Istanbul, a six-core version of Shanghai. There is nothing more to say about this one, same old same old +two cores. This was not on the roadmap a few months ago, so consider this a stopgap part.

From new we go to really new, and that is Sao Paolo, a tweaked Istanbul in 2010. The gross characteristics are the same, six-cores, 6MB L3, Barcelona-esque core, but the new stuff starts with a new socket, socket G34. From there, the cores have three new bullet points, HTC, Probe Filter and APML. Basically, this is an uncore refresh.

HTC is a new method of power control through clocking, probably very similar to what Intel does with Penryn, both under and overclocking on demand. Probe Filter is a way to lessen cache coherency traffic and speed things up for multi-socket configurations. Intel has been doing variants of this since the standout Blackford chipset, and AMD has sorely needed it. APML is more management, much akin to the hardware side of Vpro, something large enterprises get all week-kneed over.

The new socket brings two things into the mix, DDR-3 and a fourth cHT-3 link. Both are welcome and quite a bit overdue. More interesting is that both Nvidia and Broadcom are no longer on the chipset roadmap. Neither were highly regarded, and the best that could be said from either is that they were tolerated. AMD now steps up with the new ATI 8xx series chipsets which we told you about a few months ago.

There are two northbridges, the 890S and the 870S both listed as being w/IOMMU. The southbridge for both is the SB700S, not sure what the S brings to the table other than 'server' qualities, but the difference between the SB700 and imminent SB750 is basically RAID5.

It looks like AMD is going to take the the quite successful consumer SB750 and 'serverize' it. You could do a lot worse than this part, and don't expect any earth-shattering revelations here. The only one of those is NV and Broadcom leaving the market, and few tears will be shed there. I have seen this part running now, so assume there will be variants on the market long before the 2010 date.

The most interesting part is the 12-core Magny-Cours CPU. It is two Sao Paolos on an MCM. AMD isn't saying much about the configuration other than it is two dies. It doesn't take a genius to realize that they will internally wire them over HT, but the real question is whether or not they pull out all of the memory lanes. Given that Nehalem will have 6 DDR-3 channels in a few months, AMD will almost have to to remain competitive.

The last tidbit is the GT3 memory expander/BoB/microbuffer technology that AMD touted for the next gen parts seems to have gone on vacation to Montreal. Expect plain vanilla DDR-3 to stand in for it, and with MetaRAM, that should be more than good enough. µ