1. RAM, CPUs, & BUSES
Egle Cebelyte

2. What is RAM?
Random Access Memory is simply the storage area where all software is loaded and works from; also called working memory storage.

3. RAM Types DRAM- Dynamic Random Access Memory
More common type
Needs to be refreshed constantly
SRAM- Static Random Access Memory
Faster
More expensive
Rambus RAM
Advanced RAM, only used for very few Pentium 4’s
DDR RAM
A faster version of SD RAM, which is an older type

4. RAM Speeds RAM speed is measured in ns (nano seconds)
The fewer ns, the faster is the RAM
The more MB of RAM, the faster your PC
Clock speed
Time per clock tick
20 MHz
50 ns
25 MHz
40 ns
33 MHz
30 ns
50 MHz
20 ns
66 MHz
15 ns
100 MHz
10 ns
133 MHz
6 ns

5. CPU CPU- Central Processing Unit
Two main functions- 1) calculating and 2) moving data
The faster the CPU, the faster your PC

6. Moores’ Law The CPU consists of millions of transistors.
The transistors are connected by electronic tracks.
The narrower the tracks, the more transistors can be added to the CPU; hence, the speed of the CPU is increased.
In 1965, Gordon Moore predicted that the number of transistors in processors would be doubled every 18 months.

7. CPU Components ALU- the arithmetic logic unit CU- the control unit
Performs arithmetic and logical operations
CU- the control unit
Extracts instructions from memory, decodes and executes them, calling on the ALU when necessary

8. Characteristics of CPUs
Instruction set
The set of instructions that the microprocessor can execute
Bandwidth
The number of bits processed in a single instruction
Clock speed
Given in megahertz (MHz). The clock speed determines how many instructions per second the processor can execute.

9. Buses
A bus is a collection of wires through which data is transmitted from one part of a computer to another.
Two main types of buses- the system bus and the I/O buses.

10. System bus
Connects the CPU with RAM and L2- cache
Central bus

11. I/O Buses Move data Connect all I/O devices with the CPU and RAM
Main types of I/O buses
ISA bus
PCI bus
USB bus
AGP bus

12. Questions?