AMD buys (a little) breathing room with Shanghai
Quad-core Opterons just in time for IT recession
Shanghai gets its tweak on
In addition to the larger cache and slightly higher clock speeds, the Shanghai Opterons have a number of tweaks. The chips support HyperTransport 3.0 links, although this capability will not be delivered until early 2009 when AMD rolls out its own Opteron chipsets. Memory management features in the AMD-V virtualization extensions to the X64 architecture have been rejiggered to more efficiently support virtual machines as they consume memory. The chips also have compatibility features that will allow VMs to bounce across generations of AMD chips, a feature set the company calls extended migration. (Intel offers a similar feature, called flex migration).
The Shanghai chips also include a feature called smart fetch, which moves data out of L1 and L2 memories on a core that is not being used out into L3 cache and then idles the core. The net effect of this feature on a normal workload is that a Shanghai standard part can consume as little power as a Barcelona Highly Efficient (HE, for a low-voltage part) chip, which is rated at 55 watts.
As for performance, AMD is telling customers that clock for clock, a Shanghai will show about a 20 per cent performance improvement over a Barcelona chip, and that for standard chips, comparing the fastest parts, the Shanghai will deliver a 35 per cent performance improvement. As for power consumption, a Shanghai chip under load will consume about 10 per cent less juice, but chips at idle can consume as much as 35 per cent less juice than a Barcelona. This is important, since most x64 chips do not work full-out even most of the time.
In the Opteron 2000 series, which is used in two-socket servers, there are five Shanghai chips. The Opteron 2376 runs at 2.3 GHz and costs $377. The 2378 runs at 2.4 GHz and costs $523. The 2380 runs at 2.5 GHz and costs $698. The 2382 runs at 2.6 GHz and costs $873. And the 2384 runs at 2.7 GHz and costs $989. The three lowest speed parts coincide roughly with the top three Barcelona parts in terms of pricing, and they run 200 MHz slower. (These prices are for single chips bought in a volume of 1,000-unit trays, as usual).
In the Opteron 8000 series, which are used in four-socket and larger servers, there are four Shanghai chips. The Opteron 8378 runs at 2.4 GHz and costs $1,165. The 8380 runs at 2.5 GHz and costs $1,514. The 8382 runs at 2.6 GHz and costs $1,865. And the 8384 runs at 2.7 GHz and costs $2,149. The bottom two Shanghai chips have the same prices as the two top-end Barcelona parts and offer that extra 200 MHz as well.
Clock for clock, the Shanghai Opterons offer about a 40 per cent price break compared to the Barcelona chips, but Fruehe says most customers who buy servers tend to stay within a particular chip and server price band and they take the extra performance instead of downshifting their spending. That, of course, may change, given the shakiness of the global economy.
Incidentally, AMD is still selling Barcelona chips, and does so because some vendors have qualified the processor for particular products and some customers have qualified them for particular applications. But given the relatively short life-span of Barcelona - server makers started shipping products in volume only in April - and the advantages of Shanghai chips, AMD does not expect Barcelona chips to be in the product catalog for more than a year or so.
In the first quarter of 2009, AMD expects to get low-voltage Shanghai HE parts into the field as well as faster (and hotter) Shanghai SE parts for companies that just want the most performance they can get, pricing and heat be damned. Fruehe would not say if AMD would be able to break 3 GHz on the Shanghai SE parts. But it seems likely that AMD will try to break that barrier. ®