In general, upgrading memory is a simple task—assuming you purchase the proper type of memory for the upgrade. Factors that affect the proper type of memory are:

- The speed of the memory
- Pin connector type
- Parity versus non-parity

The following sections discuss each of the factors that affect the purchase of memory for your system.

Speed

When purchasing memory, you need to first take into account the speed of the memory, which is typically measured in nanoseconds (ns). SIMMs usually run between 60ns and 80ns. Make sure you don’t mix and match these speeds. The speed of the module is usually indicated on the chips themselves (by displaying either a numeric value or a simple minus sign with a number). For example, a memory module running at 70ns would show either a “70” or a “–7” on the chips.

Connectors

Another important issue with regard to memory installation is that you need to purchase the proper metal used for the pins on the memory modules. The metal used is either silver or gold. If the SIMM socket uses silver-plated connectors, the memory module you purchase must use silver-plated pins.

Parity/non-parity

The final issue with regard to memory upgrades is whether the system uses parity or non-parity memory. This information can be determined by checking the documentation that came with the system, or by trying to find the information on the Internet at the vendor’s Web site.

Installing memory

Now that you have purchased either parity or non-parity memory at the correct speed and with the proper metal-plated pins, you are ready to install the memory. After taking off the computer’s cover, you should see either SIMM banks or DIMM banks—maybe even both types. Look at the sockets and determine whether the memory modules will sit diagonally or vertically. This step is very important. I have seen many people struggle to install memory because they didn’t understand how to correctly place the modules in the bank.

If the bank is on a diagonal, lightly place the memory module vertically and then lay it back diagonally; it should just snap in. If the bank is a vertical socket, place the memory module at a 45-degree angle and lightly lay it back to the vertical position; it should snap in.

When you install the memory module, make sure you install Pin 1 on the memory module with Pin 1 in the SIMM bank. To locate Pin 1 on the memory module, look for the cut-out on the memory module and place it over the shoulder of the SIMM bank.