· 29 million transistor 0.18-micron Coppermine core
· 1GHz clock speed – 7.5x clock multiplier
· 32KB on-die L1 cache running at core speed
· 256-bit Advanced Transfer Cache - 256KB on-die L2 cache running at core speed
· Advanced System Buffering
· 242-pin Slot-1 GTL+ CPU interface running at 133MHz
· 1.70v core voltage
For starters, the 1GHz Pentium III isn’t any different from the original Coppermine based Pentium III that was released last October -- with one notable exception. Like AMD, Intel has resorted to increasing the core voltage to 1.70v from 1.65v in order to retain high enough yields on the CPUs at this frequency. The 1.70v core voltage is still within the range of tolerance for the CPU, so it is acceptable for Intel to do this.
This is a practice that most overclockers use in order to increase the stability of an overclocked system. However, when Intel or AMD does it, it’s “increasing the yield” ;)
Another interesting thing to note here is that the 1GHz product will be available only in a 133MHz FSB version, so no 100MHz x 10.0 configurations on your old BX setup; you’re slowly being forced to get rid of that BX board.
If you’re not familiar with some of the features the Coppermine core offers, the two biggest and most talked about benefits of this core are the Advanced Transfer Cache (ATC) and the Advanced System Buffering (ATB).
The ATC on the Pentium III is just the fancy name for the on-die 256KB L2 cache. Now keep in mind that the Pentium III 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 older 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 Coppermine (compared to the 4-way associative L2 cache on the old Pentium III/Celeron).
Because the 256KB of L2 cache is on-die, the transistor count of the Pentium III is increased tremendously over the 9.5 million transistors that made up the original Pentium III (Katmai) core. The 256KB L2 adds about 19 to 20 million transistors, putting the total transistor count of the Coppermine at approximately 29 million transistors.
Advanced System Buffering is a simple term that represents the increase in buffers the Pentium III Coppermine offers over the previous generation of processors, including the Katmai based Pentium IIIs. 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.