1. Random Access Memory (RAM)

2. Functions of RAM in a PC
RAM is the workplace where the CPU stores programs that are running.
CPU’s short-memory
RAM is volatile medium
It requires continuous electricity to hold data
to store data more or less permanently you need save it to a non-volatile storage (hard disks, floppy)
Dynamic Random Access Memory (DRAM) is the primary system memory

3. Address bus is used to access the chips in RAM sticks
CPU uses Static Random Access Memory
(L1 and L2 cache)
CPU directs the Northbridge chip to update and retrieve data – RAM does not directly connect to the address bus or the data bus.
PC has at least one or more small circuit boards, called sticks, usually about 4 inches long
Sticks of RAM are divided into small chips which is the actual physical location of the RAM
Address bus is used to access the chips in RAM sticks

4. RAM Technologies Fast page Mode (FPM) RAM
original type of RAM used in PCs
Obsolete
Used in Pentiums and earlier
Extended Data Output (EDO) RAM
Improvement of FPM RAM
Both EDO and FPM are asynchronous
Asynchronous RAM speeds are measured in nanoseconds (ns)
Used in Pentium II, Pentium, early Celeron and Athlon

5. Synchronous Dynamic Random Access Memory (SDRAM)
has a clock speed (Hertz)
PC66, PC100, PC133
66MHz, 100MHz, 133MHz
Double Data Rate SDRAM (DDR SDRAM)
Advanced, double speed type of SDRAM
DDR200 /PC1600, DDR266 / PC2100, DDR333 / PC2700, DDR400 /PC3200
200MHz, 266MHz, 333MHz, 400MHz
DDR2 SDRAM
PC – PC2-8500
200MHz, 266MHz, 333MHz, 400MHz, 533MHz
DDR3 SDRAM
PC – PC
400MHz, 533MHz, 667MHz, 800MHz
Rambus DRAM
Direct competitor to DDR
PC600, PC700, PC800, PC1066
400 or 533MHz

6. RAM Packages SIMMs (Single Inline Memory Module)
Two sizes: 30-pin SIMMs and 72-pin SIMMs
Need to be installed by groups of two or four which is known as banks.
Used in FPM and EDO RAM
DIMMs (Dual Inline Memory Module)
Used by SDRAM and DDR SDRAM
SDRAM – 168-pin DIMM
DDR SDRAM – 184-pin DIMM
SO DIMMs (Small Outline DIMMs) use for laptops
SO DIMMS – 200 pins

7. RIMMs (Rambus Inline Memory Module)
Use for RIMM
Uses a special stick called a CRIMM (continuity)
All slots must be filled
160 pins

8. Install RAM in a PC
Every time you load a program, it takes up some of your RAM. When you run out of real RAM on your PC, your PC will use a special part of your hard drive, called the swap file, as if it were RAM. This process is called using virtual memory.
Using virtual memory too much causes the system to slow down and the hard drive to thrash. These symptoms are the primary signs that

9. Unless a RAM chip is labeled, it is impossible to tell its capacity simply by looking at it.
Make sure that you have the right speed of RAM for your system.
Always handle RAM very carefully to prevent ESD.
Use the RAM count at bootup as your primary test to determine whether the PC recognizes added RAM.

10. Review Questions
The chip is the primary interface between the CPU and RAM.
Eastbridge
Southbridge
Northbridge
RAMBUS

11. Review Questions
Which of the following statements is true about RDRAM?
It uses dual-channel architecture.
It offers speeds ranging from 200 MHz to 600 MHz.
It is less expensive than SDRAM.
It is used by AMD but not Intel processors.

12. Review Questions
Which of the following SDRAM speeds would not work with a 100-MHz motherboard?
66 MHz
100 MHz
133 MHz
200 MHz

13. Review Questions
Which of the following is a valid package size for desktop RDRAM RIMMs?
160-pin
172-pin
184-pin
200-pin

14. Review Questions What package does DDR-SDRAM use for desktop PCs?
30-pin
72-pin
168-pin
184-pin

15. Review Questions Why is SDRAM faster than regular DRAM?
It makes two processes per clock cycle.
It runs synchronously with the system clock.
It uses dual-channel architecture.
It has fewer pins, resulting in fewer corrupt bits.

16. Review Questions What is another name for DDR400? PC200 PC400 PC1600

17. Review Questions
Joaquin wishes to upgrade the DDR RAM in his system with DDR2. Angela says he can’t because sticks of DDR2 won’t fit in the motherboard slots that currently hold Joaquin’s DDR RAM. Ben says he can use DDR2 in his system, but won’t see any speed benefit because the motherboard only supports DDR. Who is correct?
Angela is correct.
Ben is correct.
Both Angela and Ben are correct.
Neither Angela nor Ben is correct.