AMD delays faster Phenoms, juggles B3 allocations

We reported earlier today that AMD was denying problems with the upcoming B3 stepping of its quad-core processors, the new rev of the chip expected to squash the TLB erratum and, perhaps more importantly, to cast off the performance hit cause by the erratum workaround. AMD maintains that some B3-step chips are still on track for introduction this quarter, but it has delayed the introduction of faster Phenom 9700 (2.4GHz) and 9900 (2.6GHz) processors into the second quarter of 2008. Here’s AMD’s public statement on the matter:

AMD will now introduce the AMD Phenom 9700 and 9900 models in Q2 2008. This decision was based on OEM input on how AMD should prioritize its next two waves of AMD Phenom processor models. Based on these customer inputs, AMD will continue to prioritize volume-based Phenom products, including the AMD Phenom triple-core processor introduction for consumer and commercial markets this quarter, and now a new energy–efficient 65W AMD Phenom 9000e series processor in this quarter (instead of Q2). AMD Phenom 9700 and 9900 models will immediately follow next quarter.

So AMD will move ahead with triple-core and low-power versions of the Phenom in Q1, but not with higher Phenom speed grades.

An AMD spokesman we questioned insisted this decision was not the result of a delay in B3 silicon, but the result of a reshuffling of priorities for chip allocations. He characterized the ramp of B3 silicon as still "on track," beginning in Q1 and extending into Q2, with higher volumes coming later in the process. Rather than lead with higher speed grades of Phenom desktop processors, AMD will ship the first B3 chips as quad-core Opterons.

Since Opterons command higher prices than their desktop equivalents, this move could make good financial sense for AMD. That’s especially true because the TLB problem is apparently most likely to manifest in server-class workloads involving virtualization, and the firm has curtailed quad-core Opteron shipments to all but a select group of high-volume customers who are likely getting a discount on B2 chips affected by the TLB erratum.

In reality, though, AMD’s change of plans may be prompted by two issues that aren’t entirely related. Technically, the TLB erratum affects all speed grades of AMD’s pre-B3 quad-core processors, regardless of clock frequency. AMD might be skittish about introducing a higher-priced, higher-performance Phenom that isn’t based on B3 silicon because the erratum workaround can sometimes cause substantial performance reductions, and AMD has directed its PC OEM and motherboard partners to enable the workaround by default. The other, more directly related issue is AMD’s ability to deliver chips capable of running at higher clock frequencies in sufficient volumes to make the launch of a product at 2.4GHz or above feasible. The firm is likely counting on newer batches of chips to deliver the improved clock speed tolerance needed to make higher speed grades possible in volume.

One question raised by the delay of the Phenom 9700 and 9900 is the fate of the B3-rev Phenom processors at 2.2GHz and 2.3GHz, originally scheduled for release in Q1 as Phenom models 9550 and 9650. When pressed on this question, AMD would no longer commit to a Q1 release date for these products. The most likely outcome, in our view, is that these products will be delayed into the second quarter alongside the higher Phenom speed grades. In fact, AMD confirms that its triple-core and energy-efficient Phenoms will initially be based on the B2 stepping.