1.
SYSTEM PERFORMANCE

2.
INTRODUCTION
• How To Assess A Given Machine
• No Single Factor Makes a Machine Powerful
• A Good System Is That Which
(a) Upto the Task You Want to Perform
(b) Coupled With Correct Peripherals
• System Performance in General Depends Upon the
Following Factors
1. MIPS
2. Clock Speed & Landmark Speed
3. Data Transfer Rates
4. Multiple Buses and Processors
5. MFLOPS
6. Benchmarks : A Possible Answer

3.
MIPS
• Millions of Instructions Per Second
• Not a Good Indicator of System Performance
Simple Instructions > Less Time
Complex Instructions > More Time
• A Standard Mix of Instructions Is Useful
• Some Important Figures
Initial 8088 based PCs > 0.5 MIPS
386/486 based PCs > 10 MIPS
Modern Pentiums PCs > 15-25 MIPS

4.
CLOCK SPEED & LANDMARK SPEED
• Every Computer Has a Master Clock
• Therefore Program Execution Speed  Clock Speed
• Measured in MHz
• Only Meaningful in Identical Microprocessors
• Some Common Clock Speeds
1. IBM 8088 based PC - 4.77 MHz
2. IBM XT (286) PC - 8 MHz
3. IBM AT (386) PC - 33 MHz
4. IBM PS/2 (486) PC - 40 MHz
5. IBM Pentium PC - 133 to 333 MHz
• Landmark Speed “The speed at which an original IBM AT
machine would have to be run to give same performance.”
• RISC vs CISC

5.
DATA TRANSFER RATES
• Data Movement Takes Place Between
– Processor
– Memory
– Disk
– Video
• Connected Via Busses > “Information Superhighways”
• Speed of Components Effects Execution Performance
• Measured in Mbytes/s & Mbits/s
• Depends Upon
1. Clock Speed
2. Band Width

6.
MULTIPLE BUSES AND PROCESSORS
• A big question : How many microprocessors ?
• Another big Question - How Many Buses ?
• The Disadvantages of a Single Bus
1.Only Two Components Can Be Active at a Time
2. Standardization Is a Must
• One Component - One Bus Theory
• The Birth of Internal and External Buses
• Advantages of external buses
1. Economy of manufacture
2. Efficiency for customer
• Multiple Bus masters
• Dynamic Memory Access
• Wait States

7.
MFLOPS
• Millions of Floating Point Operations Per Second
• Pertains to Numeric Coprocessor or FPU (Floating Point
Unit)
• As CPU Is to MIPS
• So FPU Is to MFLOPS
• It Is an Average Measure of the FPU Power
• Ranges From 0.3 to 0.9 MFLOPS in Legacy
Microprocessors and 1 to 8 MIPS in the Modern
Microprocessors.

8.
BENCHMARKS : A POSSIBLE ANSWER
• Benchmark - “A Standard Program That Is Used to
Compare Machines.”
• Demand Profile - “ a.”
• A Very Wide Spectrum of Parameters Effect System
Performance.
• No Perfect Benchmark Exists
• Customization by Manufacturers Is Big Problem
• Four Basic Factors Involved in DP
1. The Microprocessor
2. The FPU
3. Hard Disk
4. Video Power