Intel Pentium III E "Coppermine" (Slot-1)

The Pentium III E is a much more complex processor than the original Pentium III was. While the 128mm^2 Katmai core housed around 9.5 million transistors, the 106mm^2 Coppermine core is home to around 29 million transistors. While this is more than the 22 million that make up AMD’s Athlon, keep in mind that around 19 to 20 million of these transistors are for the 256KB of L2 cache.

The chip itself operates at a 1.65v core voltage (the socket-370 or FC-PGA version operates at 1.60v) and is compatible with all Slot-1 motherboard platforms as long as they provide BIOS support for the CPU and can deliver the necessary current and voltage to the CPU.

The Pentium III E is currently available in quite a few flavors; below is a chart comparing all of the different Pentium III processors available today.

Names in Bold are based on the 0.18-micron Coppermine core
E - Denotes 0.18-micron Coppermine core
B - Denotes 133MHz FSB CPU

More than Just 256K L2

There are two buzzwords that Intel will throw at you when talking about the Pentium III E; the first is what they like to call the Advanced Transfer Cache. The ATC on the Pentium III E is just the fancy name for the on-die 256KB L2 cache. Keep in mind that the Pentium III E isn’t just a Celeron with twice as much cache and SSE, the L2 cache bus has been increased from the 64-bit bus width on the Pentium III and Celeron processors to 256-bits wide. The ATC also refers to the 8-way associativity of the 256KB L2 cache on the Pentium III E (compared to the 4-way associative L2 cache on the Pentium III/Celeron).

The second buzzword is Advanced System Buffering which is a simple term that represents the increase in buffers the Pentium III E offers over the previous generation of processors. If you are interested in specifics, there are now 6 fill buffers, 8 bus queue entries and 4 writeback buffers (up from 4, 4, and 1 respectively). These three optimizations all help to take advantage of the 1.06GB/s bandwidth offered by the 133MHz FSB.

Intel then went in and physically rearranged the die to take advantage of the 0.18-micron fabrication process. This rearrangement went hand in hand with the addition of a sixth physical metal layer that is now a part of the chip (the older CPUs featured 5 metal layers) which helps account for some of the performance improvement the Pentium III E offers.

The basic idea Intel is trying to convey with all of these buzzwords is that the Pentium III E is more than just a regular Pentium III with 256KB of on-die L2 cache. But the real question is, with all of these enhancements, can the Pentium III E beat out the Athlon on a clock for clock basis?