All Dressed Up with No Place to Go

The Athlon microprocessor from Advanced Micro Devices Inc. ( debuted with the reputation of a Pentium "killer" already in-hand. But competitors who attempt to challenge semiconductor giant Intel Corp. in the high-end symmetric multiprocessing (SMP) space often find they have their work cut out for them in engineering a scalable SMP chipset for enterprise environments.

Analysts generally refrain from predicting the next-generation processor’s promise as an SMP workhorse in the absence of a bona fide four-way or eight-way chipset. According to Nathan Brookwood, a principal analyst with market research firm Insight 64, Saratoga, Calif., AMD must first demonstrate a scalable SMP chipset before enterprise IT organizations -- not to mention large PC manufacturers, such as Compaq Computer Corp. or Hewlett-Packard Co. -- will accord Athlon serious consideration as an enterprise player.

"If [AMD’s chipset development efforts work] -- and we won’t know toward the end of this year how much progress they're making -- [Athlon] could be a very promising midrange server environment," Brookwood says. "When they finally have [an SMP chipset] in place, if the performance advantages continue to be as substantial, they will definitely be able to gain a toehold in the enterprise space."

This is easier said than done. Intel’s setbacks and frustrations in the SMP chipset design arena have been well-publicized, with repeated delays in the development of the company’s Profusion architecture. The eight-way chipset was released this past August -- nearly two years after Intel’s acquisition of Corollary Inc., Profusion’s original creator company.

With Intel’s difficulties in mind, AMD is determined not to undertake the development of an Athlon-based SMP chipset on its own, acknowledges Lance Smith, director of enterprise segment marketing at AMD.

"We’ve got two third-party partners working to develop chipsets, motherboards and total solutions for the Athlon processor," Smith says.

Athlon’s use of the EV6 bus of Compaq’s Alpha microprocessor bestows upon Athlon immediate enterprise credibility. AMD’s two partners in the Athlon chipset development effort, Hotrail Inc. ( and Alpha Processor Inc. (API,, have enterprise pedigrees of their own. API has produced Alpha chipsets and motherboards and Hotrail -- formerly Poseidon Technologies -- produced an SMP chipset for Intel’s original Pentium microprocessor.

Far from suffering some of the design setbacks that plagued Intel’s Profusion effort, Hotrail and Alpha Processor expect to deliver Athlon chipsets sometime in early 2000. Hotrail president Rick Shriner says his company first began developing the technology on which its prototypical Athlon chipset is based almost two years ago.

Hotrail’s technology, which Shriner dubs a "simultaneous switched matrix," is a switched-fabric architecture that eschews the traditional bus paradigm employed by both Intel and API, effectively putting the processors, I/O and memory onto a network.

"With a bus architecture, you do a transaction; and though you can go many transactions deep in doing it, you have to start the first one, delay, then start the second one. You have arbitration and delay on the bus, too," Shriner explains. "With the architecture we have, we can do multiple transactions at the same time, sort of like every transaction has its own bus.

For its part, API is taking a more conventional design approach by working on a 14-port crossbar switch that, Insight 64’s Brookwood says, can link up any combination of memory controllers and I/O controllers in an SMP configuration.

On paper, the proposed Athlon SMP architectures appear to offer a staggering potential for performance. Hotrail’s simultaneous switched matrix approach, for example, provides an aggregate memory bandwidth of 12.8 GB per second for all of the processors in an SMP configuration. As a point of contrast, Intel’s Profusion architecture is limited to an aggregate of 1.6 GB per second of memory bandwidth.

But having higher-performance technology doesn’t necessarily guarantee market acceptance. After all, Intel has long been on the VIP list at the enterprise ball, while AMD and its partners are still looking to finagle an invitation. Moreover, vendors such as HP, Compaq or Dell Computer ( might balk at jeopardizing already lucrative relationships with Intel by partnering with the unproven AMD in the server space.

Hotrail’s Shriner is candid when assessing the difficulties that face both AMD and its partners. "We have to prove ourselves. We’re a start-up [to them], we look like we’re only a couple of years old, so they see us as a risk in moving forward," he comments. "But on the other hand, the OEMs are very interested in seeing our first silicon, very interested in working with us in performance analysis and validation, and if the technology performs like I believe it’s going to do, they’re going to be very interested in buying it when it’s ready."