AMD Alters Course on the Way to 12 Cores - Page 2

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However, this change in design strategy makes a lot of sense to Dean McCarron, president of Mercury Research, which follows the semiconductor market.

"What I am seeing overall is they are making business decisions when they are making their technical decisions," McCarron told InternetNews.com.

"AMD is a little more sensitive to taking big risks without making financial reward now," he said. "When you have to get financial results, you get conservative."

Consequently, rather than doubling a quad-core design as it would have with Montreal, AMD instead opts for a six-core design, which will be less ambitious but will mean higher yields. That translates into lower cost of manufacturing.

Then, rather than go through the agony of making a native 12-core chip, it takes a page from the Intel playbook and uses an MCM design for Magny-Cours.

"So it makes a lot of sense from a manufacturing perspective to make both steps," McCarron said. "It's a big roadmap change, but there's a benefit coming from it."

One big difference between Magny-Cours and Sao Paulo will be clock speeds. Because AMD has pledged both will fit in the same power envelope, it means Magny-Cours' 12 cores will have to run slower than the six in Sao Paulo.

"Given the industry has made it very clear it wants to hold down on the power envelope, we can deliver higher clock speeds with fewer cores," Allen said. "At 12 cores, you have to run slower to keep the processor in the same power envelope."

McCarron said this could help AMD stay competitive with Intel.

"You have a number of avenues where they have to be competitive, like price and risk versus reward. They've lowered the risk and see a higher reward with this version of the roadmap as opposed to doing a monolithic eight-core design."

The change in plans -- and AMD's newfound risk aversion -- come as the company is seeking to rebound after a painful, protracted delay in shipping Barcelona.

One of the reasons the company lagged in getting Barcelona out the door had been the TLB errata bug, though Allen today said the bug had been extremely rare and very hard to trigger.

Still, he said AMD decided it was still worth the bad publicity to hold off shipping the processors until it was fixed.

"We ran the risk of data corruption and we couldn't risk something like that," he said. "If it were just something that caused a system crash, we might have been able to push through that."

Still, there is one computer doing just fine with those flawed Opteron chips: Ranger, the Sun Microsystems supercomputer at the University of Texas at Austin. With 16,000 processors -- for a total of 64,000 cores -- Ranger has more computing power than all other open scientific clusters combined, Allen said.

Sure, there are faster supercomputers -- like Blue Gene/L and Red Storm -- but they are operated by the military and not for public use. Any researcher can rent time on Ranger to do things like climate modeling or astronomical calculations, and Allen said time on the system is constantly sold out.

Update adds new information on the architecture of Magny-Cours and comments from McCarron.