Microprocessor - DRAM performance gap
Source: Hennesy and Patterson “Computer architecture”,
Average CPU clock rate doubles every 18 months
Main memory data transfer speeds increase 10% every 18 months
Conventional interconnects cannot deliver performance that matches improvement in CPU
1997 - 2Q AMD K6 MMX (233 - 300 MHz)
1997 - 2Q Intel Pentium II (233 - 300 MHz)
1998 - Intel Deschutes (333 - 450 MHz)
1999 - Intel Pentium III (450 - 550 MHz)
2000 - Intel Pentium III / AMD Athlon (1 GHz)
2000 - Intel Pentium IV (1.5 GHz)
2001 - 2Q Intel Pentium IV (1.7 GHz)
Processor Clock (MHz) SPECint95/2000 SPECfp95/2000
DEC Alpha 667 35/413 69.4/500
Pentium III 800 38.9/386 32.1/286
Pentium III 1000 ---/448 ---/318
Pentium IV 1700 ---/1586 ---/608
800 Mb x 16 b x 2 (400 MHz)
internal data path 12 GB/s
8250 Memory Controller Hub (MCH)
ICH 8b x 66 MHz = 66 MB/s
P64H 16b x 66 MHz = 133 MB/s