Ram tester

Advanced Testing: RAM

Sorting

• SDRAM has a notch in the middle and a notch towards one side
  • Reject if slower than 133 MHz OR smaller than 256 MB. We're only keeping SDRAM that is at least 256 MB / 133 MHz
  • If the size or speed is not obvious, use the SD-RAM tester by the KVM switch
• RDRAM or RAMBUS ram has two notches in the middle and always has EM shielding plates
  • Reject if smaller than 512 MB, otherwise put it in the store box (we no longer test RAMBUS RAM)
  • Make sure to rubberband identical pairs together
• DDR has one notch in the middle
  • DDR1 vs DDR2
    • DDR2 has a denser set of contacts compared to DDR1
    • DDR2 will usually say something like "PC2" on the sticker
    • 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
  • Speed
    • DDR1
      • 266 MHz, aka PC2100
      • 333 MHz, aka PC2700
      • 400 MHz, aka PC3200
    • DDR2
      • fixme
• SODIMMs go directly to Laptop Build, where they will be sorted and tested
• ECC memory goes directly to Server Build, where it will be sorted and tested
• Everything else, especially including 30- and 72-pin memory modules, is immediately rejected. This stuff is too old even for FreeGeek.

For RAMBUS and DDR, the speed and size are nearly always put clearly on a sticker on the ram. If it doesn't have one, you can try searching for the model number online, or you can plug it into a machine to find out. When you do find out, label it BEFORE testing.

For SDRAM, there are many considerations. You will often find that it will list the speed and not the size. In some of those cases, you can look for the size cryptically written as 4x64. In these cases, the actual size is as follows:

• 4x64 is 32 megabytes
• 8x64 is 64 megabytes
• 16x64 is 128 megabytes
• 32x64 is 256 megabytes
• 64x64 is 512 megabytes

If the speed isn't listed, it is probably 66MHz, but not always.

Parity and ECC SDRAM are weird.

Testing

1. Switch the KVM console to the correct motherboard.
2. Ensure that the motherboard with which you want to test the memory is switched off at the power supply.
3. Insert the ram into one of the motherboards placed on the wall.
   • Make sure that the bumps are lined up currectly with the holes on the RAM sticks.
   • Do not mix memory speeds (ie, one 333 MHz and one 400 MHz)
   • Try to make sure that the modules in the matching bracket-color slots matches -- has the same number of memory chips and so on. This will enable dual-channel mode (for both DDR1 and DDR2), which reduces the time required by about half
4. Turn on the power supply switch and, if needed, press the power button attached to the motherboard (they should turn on when they receive power)
5. The computer will boot up into the RAM testing program (memtest86+), then it will automatically start testing.
6. Check the RAM amount that is listed in memtest86+ is the same as what you think you put in.
   • Check for dual-channel mode at the end of the "Settings" line; subtle differences can prevent two apparently similar modules from working together
   • On some motherboards, some memory is reserved by the on-board video card. This should be less than 16 MB.
   • Some memory, especially by Kingston, may show up as half the size marked -- the listed size is for the set of two. For such modules, turn off the computer, remove the offending RAM, and mark it BEFORE testing it so that whoever removes the RAM (which may not be you) doesn't mislabel it
7. The computer will have to go through three passes before the RAM test is complete.
   • If all three passes are successful, then the RAM is good!
   • The pass numbering is zero-based, so when it starts working on pass "3", it has met FreeGeek's standard
   • If there are ANY errors, remove half the RAM, put it back in the to-test pile, and restart the test. Recycle when there is only one module in the motherboard and there are errors.
8. Label the RAM and place it in the finished ram location.
   • label should generally go in the top right corner, but can be moved to avoid covering up the manufacturer's sticker
   • SDRAM label format: "{size} / {speed}" (should be either "256 / 133" or "512 / 133")
   • DDR1 label format: "DDR {size, MB} / {speed, MHz}", such as "DDR 256 / 266" or "DDR 512 / 400"
   • DDR2 label format: "DDR2 {size, MB} / {speed, MHz}", such as "DDR2 256 / 533" or "DDR2 1024 / 667"