Skip Navigation

Installing RAM

This is a brief guide on how to put more RAM in a PC and get it to work.

RAM Basics

If you're really interested in gory details you can check out Kingston Technology's "Ultimate Memory Guide". This should give you all the SIMM/DIMM/DRAM/VRAM lingo you need to know. After that it basically comes down to this. RAM is the working memory in a computer. Most PC's on campus have between 32 and 96 Megabytes of it, and adding more is generally pretty straight-forward. These days RAM comes in the form of SIMMs and DIMMs (which look pretty much the same to the untrained eye). These memory modules have an edge with gold (or tin) contacts which slide into the motherboard of the computer into little slots made mode for that purpose. Different models of computers have different rules about what sort of memory modules can go in which slots. Kingston's page is one place to look up that sort of information, although the original system manual is probably the best bet. The memory modules come in different size increments (4 megabyte, 8 megabyte, 16megabyte, etc....). Some typical restrictions on installing memory is a requirement to install the modules in pairs (which are often required to be the same size), and/or installing certain memory in certain "banks". (The memory slots on the motherboard are often grouped into complementary banks--which is often indicated directly on the motherboard. e.g. half the slots are labeled A, and half are labeled B, indicating you have two banks of memory named bank A, and bank B). Some older PC's have even weirder memory requirements. For instance some DEC 333's require an external card to add more than 4Megs of RAM. The bottom line is make sure you have the right memory of the right type for the particular computer you want to upgrade.

RAMin' it in place.

Once you've got the right SIMMs (or DIMMs or whatever they're called this week) you get to put them into the slots on the motherboard. The general procedure is as follows.

  1. Turn off (and unplug) the computer. Make sure you're grounded any time you work inside a computer. Grounding strips around your wrist AND attached to a metal bit of the computer do the trick, as does maintaining contact between bare skin (please show decorum) and a metal bit. (Choose a metal bit on a nonsensitive part of the case like drive rail or the power supply.)
  2. Take off the case, and remove whatever bits necessary to get at the memory slots. If you need to unplug/remove any bits to get at the slots be sure you remember (or write down) how to put it all back together. There are a lot of similar looking slots on a PC motherboard (for cache and sometimes video RAM). Be sure you know where the correct slots are. (read the manual or ask)
  3. Slide the memory modules into the correct slots, making real sure they are "seated" all the way in. Various modules have different ways of going in. One popular method is to slide the module into the slot at a 45 degree angle and then tilt it upright. Newer DIMM's often go straight in from the top. Often there are little tabs on either end of the slot that snap into place and hold things together. Read the manual or ask if it isn't clear. If it doesn't look like it is all the way in it almost certainly isn't. Modules not seated all the way in are the most common memory problem by a long shot. Pull 'em in and out a few times if you're not sure. It may take a fair degree of force. Hold the modules by the ends, not touching the chips or the edge with the gold connectors. A little static and it's all worthless.
  4. Plug in and start up the computer and make sure it works. Most PC's now (Pentia?) should automatically recognize the new RAM and indicate the new total amount as they do the RAM check when they boot. If the total amount doesn't jive with what it should be dive back in and reseat the new memory. Older PC's may give an error message on boot and require you to go into the BIOS (often by holding down the F1 key), and verify (often just by saving and exiting) the new amount of memory. With extremely old machines (QS/20's) you have to run a utility off a floppy for the computer to recognize the new RAM. I won't go into this here in hopes that you never have to deal with this situation.

But it don't work!

If you do all this and the system doesn't seem to be recognizing the new memory there are several possible problems. In order of likely-hood (as far as I've seen) they are:

  1. One of the memory modules isn't seated all the way. Open things back up and pull things in and out. Find someone who's done it a few times to give it a try. Push hard (but don't break anything) It's all in the wrist.
  2. Wrong chips in the wrong slot. Check where you got 'em and make sure you're putting the right ones in the right banks and slots.
  3. Bad memory module. Maybe it got zapped by static along the way. (Hopefully it isn't your fault?). Find some others, or use memory already in the machine to play musical RAM and verify your hypothesis.
  4. Bad memory slot. As with the above problem you have swap chips around, and apply a little logic to be sure of things.

Happy memories....