Feeds

Caminogate: the plot thickens like caramel

Fear, uncertainty, doubt amounts to Intel blundering thud

  • alert
  • submit to reddit

The Essential Guide to IT Transformation

Sources close to Intel's technologies have taken time to sift through the i820 debacle (Caminogate) and have pointed to fundamental flaws in the chip firm's validation plans. (We didn't think it was long before we started writing about this stuff again -- see yesterday's Strange Whiff story). The reliable source points to an Intel developer page dealing with RDRAM validation and says that the validation process is statistically meaningless, given the number of components (from two to five) that were tested. This is the page and this the results page he has in mind. The sample size, he notes is between one and four. "I would certainly have confidence in a telephone survey that called one to four people out of a target demographic...not!", he said. The i820 and the i840, the latter of which was formally released today, use identical Rambus interface circuitry, he claimed. And there are other mobos rather than Dell (sorry Intel's) that fail with three RIMM modules. "These failures have to do with multiple back to back pipelined transfers from multiple devices on the bus. The guys at Hard OCP were given accurate information. This is a key feature of a Rambus system, to have multiple devices accessed simultaneously and driving the bus in a pipelined back to back fashion. This is where the only performance advantage for the bus will come from," he says. And the failures are not just poor board design, with some serious theoretical issues involved -- resonance being the key one. "Buses are running into quarter and half wavelength resonance effects which cause voltage margin and timing margin violations. No re-engineering of the drivers, board, or receivers will fix this problem with three RIMM systems. "Resonance effects are not limited to three RIMM systems, however, the effect here is much greater. There are reasons to believe that resonance problems can occur with two RIMM systems under extreme circumstances. It would literally take years of simulation time to simulate most of the possiblities," he adds. However, poorly designed boards will exhibit the problems more frequently than better designed boards, while server and workstation mobos (i840) are designed with more margin, and hence less chance of failure. He makes the somewhat interesting point that Caramel (i840) systems were not designed intelligently with the foresight that three RIMM busses would cause trouble. Instead, the i840 systems were designed with dual Rambus channels with two RIMMs per channel, and bus extenders when more modules were desired for greater size. Dual channels with two RIMMs each (four in total) is about all you can put in a standard form factor PC. "So the workstation chip boys lucked out," he says. Neverthless, he claims that i840 bus extender and memory riser technology is not as good as it might be. He reminds The Register of a story we wrote at IDF, pointing out that DDR, not Rambus, is the future for servers and for the Itanium Merced platform. And he also claims that Alfredo Moncayo, Physical Layer Architect for Rambus has left Intel. Moncayo invented the Rambus channel. This week, in the US, a paper on a 1.6Gb/s memory bus is being presented at a conference, in which Moncayo and Intel Rambus designer Michael Leddige will speak. According to the source, the mobo group that developed the Vancouver listened to technologists in Intel's platform architecture group, and so produced a design that didn't work. Mobo groups have to develop to the specs that PAL decides. Down at Intel Folsom, the chipset group implements the chipset design and creates the OEM design rules, so sitting in the middle of the minefield, while customers, including Dell and Compaq, with them. So while most RDRAM chips function, the i820 functions, the RIMMs function, and the systems were designed according to the right spec, the systems nevertheless fail because of fundamental problems in physics. Oh, and the 133MHz DRAM chipset interfaces do not meet the right timing in systems either. This, of course is architecture. And as we keep pointing out, that can differ from marchitecture... And talking of marchitecture... The dead hand of Chipzilla’s marketing goons appears to have fallen on the shoulder of the plucky US website taking early orders for Camino mobos. US outlet NECX Direct had full details of the Cape Cod and Vancouver mobos up on its site last week (see story Camino mobos go on sale), but the delayed (aka dysfunctional) Intel parts are now conspicuous by their absence. This calls into question Great Stan VP Paul Otellini’s somewhat rash claim that the i820 will ship before the end of the year.®

The Essential Guide to IT Transformation

More from The Register

next story
BBC goes offline in MASSIVE COCKUP: Stephen Fry partly muzzled
Auntie tight-lipped as major outage rolls on
iPad? More like iFAD: We reveal why Apple fell into IBM's arms
But never fear fanbois, you're still lapping up iPhones, Macs
Sonos AXES support for Apple's iOS4 and 5
Want to use your iThing? You can't - it's too old
Stick a 4K in them: Super high-res TVs are DONE
4,000 pixels is niche now... Don't say we didn't warn you
Philip K Dick 'Nazi alternate reality' story to be made into TV series
Amazon Studios, Ridley Scott firm to produce The Man in the High Castle
There's NOTHING on TV in Europe – American video DOMINATES
Even France's mega subsidies don't stop US content onslaught
You! Pirate! Stop pirating, or we shall admonish you politely. Repeatedly, if necessary
And we shall go about telling people you smell. No, not really
Too many IT conferences to cover? MICROSOFT to the RESCUE!
Yet more word of cuts emerges from Redmond
Joe Average isn't worth $10 a year to Mark Zuckerberg
The Social Network deflates the PC resurgence with mobile-only usage prediction
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.