Mr. Ford’s Guide to the A+ Certification Exam: How to be a computer technician

Learn how to be a computer technician and pass your A+ Certification

Ep 20 RAM

18th July 2008

What is RAM?

RAM or Random Access Memory is the “scratch pad” of the computer. It is the middleman for the slower components of the computer (like the hard drive) and the CPU. Data is loaded into the RAM that the CPU will use. It also provides a place for information to be stored from the CPU. It is like a personal assistant for the CEO/CPU.

What is the job of RAM?

Memory stores three basic things:

  1. The Operating System (OS) and other system software the computer needs to work
  2. Applications programs that are working on specific tasks (Word Processing, Solitaire)
  3. The Data that is being processed by the application

Random vs. Serial

RAM is an abbreviation for Random Access Memory, but what does the Random mean?

Imagine if you wanted to play your favorite song; it was song 3 on side A on a tape. You would have to fast forward or rewind through the other songs before you could get to that song. This type of data accessing is called Serial. Step 1, Step 2, Step 3, Step 4, etc….

Zooming to the modern age were tapes and tape decks have become ancient technology, we have the MP3 player. If you want to access a song or podcast on your iPod or other MP3 player you can directly access it. Being able to go to any spot without having to go through step 1, step 2 step 3, etc… Random access means that any individual byte of memory can be accessed at any time. All parts of memory are equally accessible.

Classes of RAM

When we start to get into the types of RAM, the aspiring tech can get a little confused. We are going to start with the two families of RAM:

  • Static
  • Dynamic

Static RAM (SRAM)

This type of RAM is incredibly fast. It is fast because it uses several transistors to hold each bit of data in memory. More importantly then that is that the data stored in this type of RAM will not decay for as long as the power is on. The more geeky explanation is that SRAM does not need to be refreshed.

Quick word about refreshing- Refreshing means the data must be re-energized. Data in Dynamic RAM will decay, fade away, disappear, or what ever you want to call it. The data must therefore be re-zapped in order to keep if there. While the computer is refreshing this data it cannot be used. For those of you who like hockey, think when the ice has to be refreshed by the Zamboni, for those of you who do not like hockey, sorry. While the Zamboni is on the ice the hockey players cannot play. They have to wait till the ice is done being refreshed.

Static RAM is supper fast because it does not need to be refreshed, therefor it does not have to wait to be used. This might sound great, but there is a prices pay for this constant state of freshness. Static RAM is boo koo expensive. Because of how expensive SRAM is, you can only find it as part of the CPU cache.

Dynamic RAM (DRAM)

This is the type of RAM that you can install and upgrade in computer. There are many different variations of DRAM but they all share a common characteristic, they must be refreshed.

To quickly recap. There are two main categories of RAM. Static and Dynamic.

The two main families of RAM: Static and Dynamic


DRAM a Closer Look

Dynamic RAM has two children. Each child grew up and had families of their own. Lets take a look at DRAM

Asynchronous DRAM

This was the very first type of RAM used in computers. It is not on the A+ exam or relevant in today’s world. Know this one thing about Asynchronous DRAM: it was asynchronous. It did not keep up with the CPU. RAM would receive operating instructions, work on it, then reply when it was ready.

So if Asynchronous RAM was a type of communication it would be a discussion board. Post your thought, idea, flame, and then wait for someone to reply back to it.

Some names used in the old days were (if you see any of these as an answer choice on the A+ exam, you can gaurnetee it is NOT the right answer):

  • Fast Page Mode (FPM)
  • Extended Data Out (EDO)
  • Burst Extended Data Out (BEDO).

Synchronous DRAM (SDRAM)

This is the second child born to DRAM. This child was smarter, more hansom and just plane better. Say hello to Synchronous RAM. If Asynchronous was posting to a discussion board, then Synchronous was like talking on Skype. Two way, real time communication.

Types of SDRAM

The first types of SDRAM were named after their bus speed.

Older Types of SDRAM

This RAM is named accordingly to the bus speed, PC66, PC100, PC133. They all used a 168-pin DIMM connection. DIMM stands for Dual Inline Memory Module, it means that each side sends different information then the other side.

  • JEDEC SDRAM
    • Ordinary SDRAM
    • Also known as JEDEC SDRAM, PC66
  • PC 100 SDRAM
    • Rated to use 100 MHz FSB
  • PC 133 SDRAM
    • Rated to use 133 MHz FSB
    • Should be compatible for machine that need PC66 and PC 100

New SDRAM Technology

  • DDR SDRAM
    • DDR stands for Double Data Rate.
      • The old SDRAM could only read/write once a cycle, the double data rate could read/write twice per cycle.
      • SDRAM used to be measured by their bus speed the newer DDR was measured by the Bandwidth/Throughput.
      • DDR can give 64 bits/8 bytes of information in one shot.
      • Take the 64 bits times the amount of information that can be access per second. This lets us know how fast the RAM is.
        • For example: DDR200 chips can transfer 8 bytes of information 200 million times per second, so it is called PC 1600. 8 x 200 = 1600
      • For the A+ exam you must understand and be able to take one piece of information like the PC speed rating and covert it to the DDR Speed rating. Or vice versa. Do not memorize the chart but understand how they get the numbers.
  • DDR II SDRAM
    • Has the following befits over DDR:
      • Increased Performance
      • Increased Bandwidth
      • Reduced Cost
      • Lower Power Consuming (Good for laptops)
      • Improved packaging
        • 240-pins Connection
          • DDR uses 184-pins
        • Notches are slightly different
          • Prevents the installation of DDR2 in a DDR machine
  • DDR3 SDRAM
    • 30% reduction in power consumption compared to DDR2
    • Higher bandwidth
    • Uses 240-pins (like DDR2)
      • DDR2 and DDR3 are the same size but have different notch location (prevents putting the wrong stick in the computer)
  • Rambus DRAM
    • Got its name from its creator Rambus Inc.
    • Uses a proprietary dual-channel technology
    • Very good performance but typical more expensive
    • Found in Pentium 3 and early Pentium 4 computers
    • Never found in AMD systems!
  • Rambus Sticks
    • A stick of Rambus is called a RIMM
      • RIMM does not officially stand for anything
    • Comes in 84pin, 168pin, & 242pin

The different types of DRAM


Find the Right RAM

What you do not know can really, really cost you money. Not that long ago I was looking for a memory upgrade for my MacBook Pro. Through the Apple store it was going to cost me about $1,000 to max out my laptop. I went looking else were and found the memory I needed for about $100. Wow, that is just a slight difference.

There are three places I recommend to get your RAM. None of them sponsor me. Crucial.com, and Kingston.com have great website that will walk you through the process of finding the type of RAM you need. Both manufactures are trusted names in RAM. I also like to use Newegg.com. Some of Newegg’s RAM is brands I have never heard about, but they have a great customer rating tool that can really help you choose the right RAM for you.

 
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Ep 19 Were have you been?

18th July 2008

Where Have You Been?

Check out this podcast to hear what has been going on. I also have some exciting news!!!!

 
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Ep 18 Microprocessor Models part 03

23rd May 2008

Modern CPUs

Today’s technician should have a casual acquaintance with older CPU technology. It is important to know the major breakthroughs in CPU technology, as well as the names of the older Intel and AMD CPUs. Luckily for the modern computer technician the days of having to memories caches, CPU speeds, and sockets/slots have (thankfully) come to an end.
When dealing with the newer CPU innovations and features the competent technician should be more then just slightly aware of their workings. The good technician should be ready to let lose the inner-geek and learn (read memorize) the specification of modern CPU. Consider it a right of passage.

Eighth Generation

In 2001 the first 64-bit CPU was released, Intel’s Itanium. In case you missed the release, that was ok, the Itanium was for servers. Intel followed up on the Itanium with the Itanium 2. AMD fired back with their 64-bit CPU, the Athlon 64 and Opteron. Unlike Intel’s 64-bit chip, AMD made the Athlon 64 for the consumer market. The Opteron was their server version.
Intel wanted to capture some of the consumer’s desire for a 64-bit chip, so they created a 64-bit enabled version of the Pentium 4.
AMD release the first consumer grade 64-bit chip and looked like it was going to dominate the eighth-generation market. Intel was far from out of the game. Up until now Intel was the second CPU to break 1 GHz, they were the second CPU to go 64-bit for consumers. Intel’s new chip was about the change the face of the computer market. Intel released the FIRST dual-core processor called the (drum roll please) Pentium D.
When 64-bit came out there was a lot of talk amongst techs. For years consumers only had 32-bit chips. The release of 64-bit processors was exciting, then some ugly realities came to light, namely the 3 conditions required for 64-bit processing to be truly 64-bit processing.

  • Ugly Fact #1:
    • Hardware
      • Must have a 64-bit processor
      • Must have a motherboard that supports 64-bit processing
  • Ugly Fact #2:
    • Operating System
      • Must have an operating system that supports 64-bit processing
      • Microsoft created modified versions of Windows XP to support 64-bit processing,
        • Windows XP 64-bit Edition for the Itanium
        • Windows XP Professional x64 Edition
      • 64-bit is also available for all editions of Windows Vista except Starter
      • Some versions of Linux also support 64-bit processing.
  • Ugly Fact #3
    • Programs
      • A great deal of the programs on the market were written for 32-bit processors.
      • For 64-bit processing to be fully realized, programs must take advantage of this new architecture
      • Some 32-bit programs will run slower on a 64-bit chip then a 32-bit chip.

64-Bit CPU Specs.

Itanium
The Itanium series were powerful server processors. They were the first Intel CPUs to have L3 cache built into the chip.

Itanium

Itanium

Retrieved from: http://en.wikipedia.org/wiki/Image:Itanium.png on 10/19/07

Itanium:

  • 733Mhz, 800Mhz
  • Could access 16TB (that’s Terabytes) of RAM
  • Had a 96KB L2 Cache, and either a 2MB or 4 MB L3 Cache
  • Used a PAC418 Socket

Itanium 2

  • Processors speeds: 900MHz–> 1.66GHz
  • Could have a 400MHz, 533MHz, or 667Mhz CPU bus (the Itanium 1 had a 266Mhz bus)
  • 128-bit wide CPU Bus, the Itanium 1 had a 64-bit wide bus
  • L2 Cache 256KB, L3 Cache up to 9MB
  • Used a PAC611 socket

AMD Athlon 64

  • Came out September 2003
  • It was the 1st 64-bit processor marketed to the average consumer
  • Speeds from 1.8GHz –> 2.4GHz
  • Socket 754 & 939
  • 128KB –> 1MB L1 Cache
  • 512KB or 1MB L2 Cache
  • Could access up to 1TB of RAM

Athlon 64

AMD Athlon 64

Retrieved from: http://en.wikipedia.org/wiki/Image:Athlon-64-Lenara-CG.jpg 10/19/07

Socket 754

Socket 754

Retrieved from: http://en.wikipedia.org/wiki/Image:Socket_754.jpg 10/19/07

Socket 939

Socket 939

Retrieved from: http://en.wikipedia.org/wiki/Image:Sockel-939.jpg 10/19/0

Athlon 64 FX

  • Similar to the Athlon 64 but had the following added benefits:
  • Speeds from 2.2GHz –> 2.8GHz
  • Had a 1MB L2 Cache standard
  • Used socket 939 & 940

AMD Sempron

  • The Pentium had the Celeron, AMD had the Duron
  • The AMD Sempron is similar, it is a scaled down version of a more expensive chip
  • The first Sempron was designed to be a replacement for the more expensive Athlon XP and the Athlon 64
  • The Athlon XP Sempron used a Socket 8
  • The Athlon 64 Sempron used a Socket 754

AMD Sempron

AMD Sempron

Retrieved from: http://en.wikipedia.org/wiki/Image:Sempron-3000.jpg 10/20/07

AMD Opteron

  • Released April 22, 2003
  • This is AMD version of the Server 64-bit CPU
  • Came in single and dual-core designs
  • 128KB L1 Cache
  • 1MB L2 Cache
  • Clock speeds 1.8GHz–> 2.8GHz
  • Socket 939 or 940
  • Maximum 1TB of RAM
  • There were 3 types of CPU in the series:
    • 100
    • 200
    • 800

Dual-Core

Before we start the Dual-Core section, lets begin by saying that the Dual-Core is simply the Awesome!
Back in the olden days, servers and very expensive personal computer would come with two or more CPUs. This was the only way you could truly get multiple processing power. With the creation of the Pentium 4 came HTT, Hyper Threading Technology. The P4 would create a virtual world were some program would think they were being used in a dual-core environment.
Intel released the first dual-core chip (Pentium D, and Pentium Extreme Edition). This chip was actualy two processors, yes two processors, within one package. Now for the very first time the average consumer could have two processors within their system! AMD followed up with their release of the dual-core Opteron and Athlon 64 X2 CPUs

Dual-Core CPU Specs

Intel’s Dual-Core

  • Pentium D and the Pentium Extreme Edition 840
  • 2.8GHz –> 3.2 GHz
  • 800MHz processor bus
  • 2MB of L2 Cache (1MB per core)
  • Socket T (LGA 775)
  • The Core 2 (released on July 27,2006) succeeded the Pentium D

AMD Dual-Core

  • AMD released the Athlon 64 X2 and the Dual-Core Opteron Processor
  • The Athlon 64 X2 had four core designs
    • Manchester Core
    • Toledo Core
    • Windsor Core
    • Brisbane

Athlon 64 X2 Cores

  • Manchester:
    • 939 Socket
    • Ran from 2.0GHz –> 2.4GHz
    • 1MB (512KB per core) L2 Cache
  • Toledo Core:
    • 939 Socket
    • Ran from 2.2GHz –> 2.4GHz
    • 2MB (1MB per core) L2 Cache
  • Windsor Core
    • Socket AM2
    • 2.0MHz –> 3.0MHz
    • 2MB (1MB per core) L2 Cache
  • Brisbane
    • Socket AM2
    • L2 Cache 1GB (512KB per core)
    • 1.9MHz –> 2.7MHz

AMD Athlon 64 x2

The AMD Athlon 64x2

Retrieved from http://en.wikipedia.org/wiki/Image:Athlon_64_X2_E6_3800.jpg 10/20/0

Dual-Core Opteron

  • Used a Socket 939
  • Ran at 1.8GHz –> 2.4GH
 
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