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Pipeline Speedup

  • Are deeper pipelines better?
  • Pipelined inst time = inst time / # pipeline stages
  • 5 stages = 5X faster under ideal conditions
  • P&N DLX RISC 5-stage
  • Pentium 5-stage integer 2 pipes (1 simple inst only)
  • 8-stage FP (uses integer pipe +3 stg)
  • Pentium II/III 10-stage (25 stage FP)
  • Pentium 4 20-stage
  • Athlon 10-stage (3 pipes) + 3 15-stage FP
  • PowerPC G4 RISC 4-stage
  • PowerPC G4e RISC 7-stage
  • PowerPC G5 12-Stage (4 pipes)