AMD's Athlon CPU: A New Era?

by Alan Zisman (c) 1999. First published in Canadian Computer Wholesaler, August 1999

In the quest for the most powerful, the gold medal has usually been held by Wintel standard-bearer Intel?s processors. (At least if we talk about PCs? I know all about PowerPCs, Mac-fans, you don?t need to write).

Intel?s competitors, AMD, Cyrix, Centaur, and the rest have tended to be the bottom-feeders of the computing world?producing processors aimed at the low-cost, low-profit end of the market, while leaving the technological cutting edge, along with its cutting-edge profits to Intel. The competition often produced faster versions of CPUs than Intel ever did?but only after Intel had moved on to a newer product line.

Those days may have ended with the June release of AMD?s K-7 processor?now being marketed under the name Athlon.

Personally, I don?t like the name, and feel like it loses some of the momentum the company has built behind its respectable K6 and K6-2 product lines. But there?s no doubting the processor?s speed and power?whatever its name, with versions running at up to 600 MHz (along with lower-cost 500 and 550 MHz versions), the Athlon/K-7 speeds right past Intel?s current offerings.

Of course, megahertz alone doesn?t mean much (as Macintosh PowerPC fans will point out). You can?t simply compare two processors by clock speed alone. AMD?s new design includes many advanced features.

There?s 128 kb of high-speed cache built right onto the CPU itself. With this as Level-1 cache, the cache within the cartridge becomes the L2 cache, while cache-RAM on the motherboard becomes L3 cache. By being built right onto the CPU, the L1 cache offers very fast access, with fallback to the L2 and L3 cache-RAM as needed.

The Athlon marks the first time that any of Intel?s competitors have left behind a Pentium-style design. The processor ships in a Pentium-II style cartridge that is, in fact, mechanically identical to that Intel model. The keyword here is ?mechanically??while the Athlon cartridge will fit into the Slot One on a motherboard designed for an Intel cartridge, it won?t actually work there. Instead, it requires an electrically different design, built especially for the Athlon, using the EV6 bus protocol originally designed for the Alpha CPU.

And that?s both good news and bad news.

The new design allows motherboards built for the Athlon to run at 200 MHz?far in excess of the 133 MHz speed of Intel?s top products. The EV6 also supports scalable multiprocessing, for high-end designs with multiple processors?a market that has been, until now, owned by Intel. But it also means that manufacturers have to be committed to using the AMD processor?they can?t just plug it into an existing system board design. We?ll have to wait to see about availability.

The Athlon is being built by AMD using 0.25 micron technology at their Austin, Texas fabrication plant. The company has been hurt by production problems in the past, making it difficult to produce all the CPUs they could sell?they seem to now have the system under control for the K-6 product lines, and hopefully will not be plagued with the same sorts of problems getting the new product out the door.

Prices range from US$699 for the 600 MHz version down to US$324 for the 500 MHz version.

Pushing up the speed and power of computer systems does not always go smoothly, however?not even for market leader Intel. For instance:

  • Don?t even think about it?

Combining Intel?s low-cost 810 chip set with the company?s high-end Pentium III processor. Due to an error in the P-III?s new multimedia instruction set, known as MaskMovQ, the P-III simply will not work with motherboards built around the 810 chip set. And while Intel has released a workaround for the MaskMovQ error, it doesn?t support the fix with the 810 series, claiming that chipset was designed as a low-cost system for the low-cost Celeron processor. Intel spokesperson Dan Francisco suggested, to InfoWorld, that use of a P-III processor with an 810-based motherboard could result in a hung system. He, however, suggested that some fringe manufacturers, aiming for a cost-advantage might just go ahead and produce such a system anyway.

The 810 integrates 3D graphics, and allows for cost-saving software modem and audio functions. Reports are that Intel will be launching several other chipset models (810E, 820, and 840) in September, along with 600 MHz P-III and Xeon CPU models. The 820, code-named Camino, is expected to offer a 133 MHz system bus, along with 4X AGP video support, and is designed to be Intel?s mainstream product line. In the meantime, the current 810 chipset will work as advertised with current 466 MHz and upcoming (in August) 500 MHz Celeron processors.

  •  Faster RAM? Maybe not this year

Widespread adoption of the 820 chipset models, however, may take a while?the faster system bus speed requires faster memory. Intel had been counting on use of RDRAM (Rambus Dynamic RAM) as the answer, but reports at the spring Computex Trade Show in Taipei were that high prices and disappointing performance for RDRAM was leading to a reluctance by motherboard manufacturers to leap into production. RDRAM, currently running at 400 MHz, and with the potential of running as fast as 1.6 GHz, has been touted by Intel as the way systems could leap past limitations in system performance tied to RAM speed.

Early systems based on the 820 chipset will instead use current 100 MHz SDRAM, trading performance for a pricing advantage?especially with some manufacturers suggesting that the improvements due to the use of RDRAM simply are not dramatic enough to justify the increased cost.

  • Don?t hold your breath

Waiting for USB version 2, that is. While the first-generation USB has been slow to gather momentum, there are already concerns about its 12-Mbps data rates, limiting it to relatively low-speed devices. Instead, Apple-developed Firewire (aka IEEE 1394) has been touted for disk drives, digital video, and more. USB 2.0 promises 120-240 Mbps, however?not up to Firewire?s potential of 800 Mbps, but still plenty hot, especially combined with backward compatibility with generation-1 USB devices. The problem becomes one of too many choices. Should a digital camera manufacturer design for RS-232 serial port? USB (1 or 2)? Firewire? SCSI?

Pretty soon, high-end PCs may be offering parallel, serial, USB, Firewire, Ethernet, SCSI, and infrared ports?confusing for the user and for device manufacturers alike. Add in redundant PS/2 mouse and keyboard ports. Hopefully, PC manufacturers will instead follow Apple?s example (and Microsoft and Intel?s advice) and simplify, dumping parallel, serial, and PS/2 ports entirely, while making SCSI and Firewire optional for higher performance (and higher priced) models.

Search WWW Search

Alan Zisman is a Vancouver educator, writer, and computer specialist. He can be reached at E-mail Alan