Ram Testing

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Introduction

At this station you will test RAM (Random Access Memory). RAM acts as the short-term memory of the computer. Without it, nothing on a computer works--no display, no processing, no input/output of data. There's three steps to RAM testing at Free Geek Vancouver: Untested Sorting, Testing, and Tested Sorting.

Untested Sorting

There is a wide blue bin on top of the worktable, just under the testing boards. This is the incoming RAM bin. The first thing you should do, before you get to testing, is sort the RAM from this bin into the smaller bins in the shelves under the tabletop. The RAM you find in the incoming bin is completely unsorted and untested--you will find every kind of RAM under the sun here, and it's your job to sort out the modules we want and the ones we don't. You will put the RAM modules we want to test in the smaller bins, according to their type, size, and speed. The ones we are going to scrap right away for recycling will go in the clear plastic bin on the floor under the workstation table.


The Different Types of RAM

Here's an overview of the kinds of RAM that you'll encounter when sorting. The speeds and capacities we keep are in bold.


  • SDRAM has a notch in the middle and a notch towards one side (2 notches).
    • SDRAM is the basis for all other modern RAM--DDR1, DDR2, DDR3--and looks similar to all of them.
    • SDRAM has the same chips as DDR1.
    • We don't keep any SDRAM anymore. All of it goes into the scrap bin.


  • RDRAM or RAMBUS ram has two notches in the middle and always has metal shielding plates (2 notches).
    • We don't keep any RDRAM anymore. All of it goes into the scrap bin.


  • DDR1 has one notch in the middle (1 notch).
    • DDR1 is similar in appearance to SDRAM, DDR2, and DDR3.
    • DDR1 has the same sized chips as SDRAM, but only 1 notch.
    • DDR1 has 184 contacts.
    • DDR1 comes in capacities of: 128MB, 256MB, 512MB, 1024MB/1GB.
    • DDR1 comes in speeds of: 100mhz (DDR-200), 133mhz (DDR-266), 166mhz (DDR-333), 200mhz (DDR-400).


  • DDR2 has one notch in the middle (1 notch).
    • DDR2 has a denser set of contacts compared to DDR1 (240 instead of 184).
    • DDR2 has smaller, squarer chips than DDR1 and SDRAM.
    • DDR2 will sometimes identify itself as "PC2", which is the same as DDR2.
    • If you're still unsure, you can try comparing the stick in question with one of a known type by putting them side by side, with the pins touching.
    • DDR2 comes in capacities of: 128MB (rare), 256MB, 512MB, 1024MB (1GB), 2048MB (2GB).
    • DDR2 comes in speeds of: 400mhz (PC-3200), 533mhz (PC2-4200), 667mhz (PC2-5300), 800mhz (PC2-6400), 1000mhz (PC2-8000), 1066mhz (PC2-8500), 1200mhz (PC2-9600).


  • DDR3 has one notch 2/3 of the way to one side (1 notch).
    • DDR3's chips are slightly smaller than DDR2's.
    • DDR3 looks similar to DDR2, but the difference in notch positions is a giveaway.
    • DDR3 comes in capacities of: 512MB, 1024MB (1GB), 2048MB (2GB).
    • DDR3 comes in speeds of: 400mhz (PC3-6400), 533mhz (PC3-8500), 666mhz (PC3-10600), 800mhz (PC3-12800), 933mhz (PC3-14900), 1066mhz (PC3-17000).


  • SODIMMs are laptop RAM.
    • SODIMMs have a variety of notch configurations.
    • SODIMMs are the same size as SDRAM/DDR1/DDR2/DDR3, but half as wide.
    • Put all SODIMMs in the yellow laptop RAM box.


  • ECC and Registered RAM are special derivations of the main types (SD, DDR1/2/3), and have similar notch configurations to them.
    • ECC is special server RAM that has an odd number of chips. ECC sometimes has an extra chip between the main rows of chips. The chips may also be thicker or there may be many more of them.
    • Registered (also known as fully buffered) RAM has different notch position than normal, and won't fit into any of the testing boards at FG.
    • All ECC/Registered memory go in the DDR1/2 ECC/Registered memory bins.


  • All the other kinds of RAM not listed go into scrap.


Tips: If it's less than 512MB, it goes to scrap. If it has 2 notches, it goes to scrap.

Testing

Tested Sorting