Installing memory is fairly easy, you just need to be careful. Below, you will find information on the Ram Modules, backing up your computer, tools & workspace and static prevention. You will need to know this information before you start taking your computer apart.

Things You Need To Know About Ram

1. The type of RAM for these computers is called 'SDRAM' and the module itself is called a 'SO-DIMM' or just 'DIMM'. They come in two physical sizes, regular and 'Low Profile'. The next paragraph will explain the use for the two sizes. Both PC66mhz and PC100mhz modules will work but PC133mhz will not (only half of the memory will be recognised if you use a PC133mhz module). Presently, they also come in a number of RAM sizes, 32mb, 64mb, 128mb & 256mb. Modules larger than 256mb are now available but I do not know yet if they will work on these models of iMacs.

2. There are two slots available for adding memory, a top and a bottom slot. The top can handle both regular and low profile sizes but the bottom slot can only handle low profile modules. So you have to take this into consideration when buying your RAM. For example, you could buy one 256mb low profile RAM module and put it in the bottom slot. If you presently have 32mb in the top slot, that would bring your total RAM memory to 288mb. If you wanted to spend a little more you could buy a second regular sized module of let's say 128mb for the top slot for a total of 384mb. Of course there are many different combinations you could use. Much depends on which RAM modules are available for which price.

P.S. You can find information on what RAM is presently installed on your computer by using the Apple System Profiler application that comes with most Macs. In the main window, click on the System Profile tab and look for the Memory Overview heading and click the little triangle to open it. Then click the triangle next to the Built-in Memory heading and you'll see all your memory and its location(s).

3. When purchasing Ram make sure you are buying the correct modules. It is easy to confuse the different types of memory available especially if you are ordering online. If you are not sure, try to purchase from a company that you can order by phone or buy in person. That way you can ask a real person (hopefully) for the RAM modules for your exact model of iMac (233, 266 or 333mhz). Remember, be sure to specify regular or low profile modules. Ram Seeker is a good place to look for memory online and about half the companies have telephone ordering.

Check Your Firmware.

Before doing this upgrade you must have the latest Firmware Update installed on your computer. Firmware is programming that is inserted into the ROM (read only memory) on your computer. The ROM is a chip that is permanently wired to the motherboard of your computer and should not be confused with the RAM (random access memory). ROM contains the programming that allows your computer to be booted up each time you turn it on. All early model iMacs (233mhz, 266mhz & 333mhz) need to have iMac Firmware Update v1.2 installed before upgrading the RAM memory. If you don't know if your Firmware is updated or not, you can download the updater from Apple (above link) and try to run it. It will tell you if it is needed or not. If it is needed, read the "Read Me" file and follow the instructions carefully.

Backing Up Your Data

Before starting this upgrade you should backup your iMac hard drive. If you have a CD or DVD burner you can easily backup the entire contents of your hard drive to CD's or DVD's or better yet, use an external USB hard drive. However if you don't have a CD/DVD burner or external hard drive you will have to use some other type of data storage. There is Internet backup services that will store your data on a remote computer, but space is limited.

Static Electricity

A is used to prevent static electricity from damaging the sensitive components like the Ram in your iMac. It physically connects your body to the chassis of the computer, thereby providing a safe route for the static to travel though. Consequently, if you don't use a static strap and you touch a sensitive component on the computer, the static charge that is built up in your body could travel from your finger to the component and instantly damage it. These straps can be purchased at your local electronics store but if you are a little bit inventive or just plain cheap like me, you can . In order for the Static Strap to work you need to have one end taped to your skin, usually wrist or ankle and the other end needs to be clipped to the frame of the once it is out of the computer.