Unlike the previous Duron releases, the new 1 GHz represents a new and improved core. This doesn't translate into the much-anticipated shift to the 0.13-micron die size, as the Duron Morgan core is still produced using the current 0.18-micron process.

The Duron 1 GHz also features the same 128KB L1/64KB L2 cache as past Duron models, which still compares well to the 32K L1/128K L2 cache design of the Intel Celeron and the 32K L1/256K L2 format of the Pentium III. The system bus of the Athlon remains the same at the standard 200 MHz DDR bus speed of the previous Spitfire core. As we know, the AMD EV6 DDR (Double Data Rate) bus transfers data on both the rising and falling edges of the clock, and turns a 100 or 133 MHz FSB (front-side bus) effectively into a 200 MHz or 266 MHz DDR bus.

This also means that the Duron 1 GHz will still have to take a backseat to the Athlon in terms of system bandwidth. At the 200 MHz DDR system bus, this translates into a potential bandwidth of 1.6 GB/sec, compared to the 2.1 GB/s of the Athlon 266 MHz DDR processors. Of course, this only compares the Duron to its 266 MHz Athlon sibling, and these specifications look much better next to the Intel Pentium III 133 MHz FSB (1.06 GB/s) or Celeron 100 MHz FSB (800 MB/s) CPUs.

Other than the natural 50 MHz progression up from the Duron 950, you may be asking yourself exactly what has changed between the Duron 950 and 1 GHz. The first difference is in the physical die size, which has changed from the relatively square shape of the original Duron to more of a rectangle, similar to the current Athlon core, and exactly the opposite transition the Athlon 4 took. This new core shape is due to architectural and performance enhancements, which are similar in nature to the ones AMD employed when moving from the Athlon to the newer Athlon 4 design. The two main core enhancements are the addition of a Data Prefetch function and including a new and improved 3DNow! Professional (which is equivalent to the Pentium III SSE) instruction set.

Data prefetch essentially tries to predict which data the processor will require and then loads it into the data cache. This feature can lend a bit more performance to any given processor and as the Pentium 4 has shown, it has some definite advantages with certain applications. Adding 52 new instructions to create the 3DNow! Professional instruction set now makes the Duron line SSE-compatible and removes one of Intel's main selling points, especially with the Celeron. Now when you load up Quake 3 with the Duron 1 GHz, the text message that Pentium III optimizations are being used, flashes gratifyingly on the screen.

In terms of overall performance, expect the enhanced data prefetch portion of the Duron 1 GHz to make up a large percentage of its gains. Having the SSE-compatible 3DNow! Professional doesn't hurt, but not all applications are SSE-enhanced and this feature simply can't make the same kind of performance impact across the board.

These improvements have resulted in a slightly higher transistor count for the Duron 1 GHz, from 28 million for the older Spitfire design to 28.12 million for the Morgan core. Since there a few portions of the Athlon 4 design that are naturally not included, this accounts for the lower (both literal and percentage-wise) transistor increase for the Duron's Morgan core.