Duron logo
Duron logo

Duron is a line of budget x86-compatible microprocessors manufactured by AMD and released on June 19, 2000. Duron was intended to be a lower-cost offering to complement AMD's then mainstream performance Athlon processor line, and it also competed with rival chipmaker Intel's Pentium III and Celeron processor offerings. The Duron brand name was retired in 2004, succeeded by AMD's Sempron line of processors as their budget offering.

Performance

The original Duron processors were derived from AMD's mainstream Athlon Thunderbird processors, the primary difference being a reduction in L2 cache size to 64KB from the Athlon's 256KB. This was a relatively severe reduction, making it even smaller than the 128KB L2 available on Intel's competing budget Celeron line. However, the originating Thunderbird architecture already featured one of the largest L1 caches at 128KB (which was not reduced in the Duron) and also introduced AMD's switch to an exclusive cache design which effectively unified the L1 and L2 caches. Because of this, the Duron behaved as if it had a high-speed 128KB cache combined with a somewhat slower 64KB segment giving an effective 192KB cache, versus the traditional inclusive cache design where the L2 cache had to store a duplicate of the data stored in the L1 cache. As a comparison the inclusive design of the Celeron effectively reduced the available size of the Level 2 cache by the size of the Level 1, which resulted in an effective size of 96KB (128–32) in contrast to the Duron's exclusive design (128+64=192).

Consequently, the Duron inherited the Thunderbird's reduction in sensitivity to L2 cache size, allowing AMD to make their L2 cache higher latency and lower bandwidth to lessen processor complexity and allow better manufacturing yields without incurring a significant performance loss. The net result was that the budget Duron "Spitfire" CPU was roughly only 10% slower than an equivalently clocked (and significantly more expensive) Athlon "Thunderbird".

Compatibility

The Duron line was pin-compatible and operated on the same motherboards as the Athlon line, requiring only a BIOS update in most cases. The original Duron was introduced with a 100MHz (effectively 200MHz) front-side bus– the same as the then current Socket A Athlons. Later with the introduction of motherboard chipsets offering higher FSB speeds of 133MHz (FSB 266) and AMD's matching introduction of Athlon "C" processors supporting this speed, the Duron initially retained the 100MHz FSB for purposes of market segmentation. Later Durons were given official support for 133MHz bus operation only after the Athlon XP was used to introduce 166/200MHz FSB (FSB 333/400) speeds.

Revisions

The original Duron, using the "Spitfire" core, was manufactured in 2000 and 2001 at speeds ranging from 600 to 950MHz. It was based on the 180nm "Thunderbird" Athlon core.

The second-generation Duron, the "Morgan" core, was sold in speed grades between 900 and 1300MHz, and was based on the 180nm "Palomino" Athlon XP core. As a result, it featured a few important enhancements, namely full Intel SSE support, enlarged TLBs, hardware data prefetch, and an integrated thermal diode. Like the "Palomino" core, "Morgan" was also expected to reduce heat dissipation; however in "Morgan"'s case this did not happen due to its increased core voltage.

A third-generation Duron, the "Appaloosa" core, was announced in the 2001-2002 AMD Processor Roadmap, to enter production in 2002; this was to be manufactured with AMD's upcoming 130 nm process. Despite rumors of early limited circulation however, "Appaloosa"-based Durons never reached the market, and by the end of 2001, "Appaloosa" had been removed from the roadmap.

Instead of the canceled "Appaloosa" core, the Duron line eventually saw a final generation in 2003, in the form of the "Appalbred" core (later typically misspelled as "Applebred"), which was a 130nm "Thoroughbred" Athlon XP with only 64KiB (¼) of L2 cache enabled. The name "Appalbred" was a portmanteau of "Appaloosa" and "Thoroughbred", much like the contemporary "Thorton" Athlon XP, a "Barton" with only 256KiB (½) of L2 cache enabled, was a portmanteau of "Thoroughbred" and "Barton". Neither "Appalbred" nor "Thorton" ever appeared on an official AMD processor roadmap.

In the years following its introduction and the withdrawal of the Duron line from the market, the spelling "Appalbred" gradually became replaced by the phonetically similar "Applebred", as "Appaloosa" and the etymology of "Appalbred" were mostly forgotten.

Enthusiasts

Duron was often a favorite of computer builders looking for performance while on a tight budget. In 2003, the "Appalbred" Duron was available in 1.4GHz, 1.6GHz and 1.8GHz grades, all on a 133MHz (FSB 266) bus. Enthusiast groups quickly discovered these Durons to be rebadged "Thoroughbred B" cores with 192KiB (¾) of L2 cache disabled and possibly defective. With a basic CPU OPGA package configuration modification, it was found that "Appalbred" Durons could be turned into "Thoroughbred B" Athlon XPs, with full 256KiB cache, with a very high success rate. However, this was only possible for a period of approximately 4 weeks, as shortly after "Appalbred" was released, AMD made changes to the OPGA package that made these configuration modifications ineffective.

Features

Duron core data

Spitfire (Model 3, 180 nm)

"Spitfire" Duron, 600MHz
Die shot of a Spitfire Duron

Morgan (Model 7, 180 nm)

"Morgan" Duron, 1.3GHz
Die shot of a Morgan Duron

Camaro (Model 7, 180 nm)

"Camaro" Mobile Duron, 850MHz
"Camaro" Mobile Duron, 850MHz

Appalbred aka Applebred (Model 8, 130 nm)

"Appalbred" Duron, "A"-model, 1.6GHz

See also

Further reading

  • , by Christian "Grampa", January 7, 2004, retrieved January 9, 2006, at theWayback Machine(archived July 18, 2011)
  • by Sandpile.org, retrieved January 9, 2006
  • 2018-11-10 at theWayback Machine by AMD, June 4, 2000, retrieved January 13, 2006

External links

  • – Popular hardware review website Anandtech compares low priced CPUs
  • AMD Duron processor images and descriptions