Hardware Reference
In-Depth Information
RAM
RAM is a fairly easy upgrade. The main concern is whether you have the available slots
in which to place it. In some systems, all the RAM slots already fi lled. That means if you
want to increase the amount of RAM, you must remove any lower-capacity RAM that you
already have installed and replace it with new, higher-capacity RAM.
Thirty-two bit versions of OSs can support no more than 4 GB of RAM, so don't
waste your money on upgrading RAM past 4 GB unless you're using a 64-bit
OS. Windows XP and higher comes in both 32-bit and 64-bit editions. Mac OS
X doesn't have separate editions like that; the latest versions are 64-bit.
In a desktop PC, check the documentation that came with the PC before buying RAM
to make sure there are no special requirements. For example, if the motherboard uses
dual-channel RAM, RAM must be installed in matched pairs and in certain RAM slots.
For example, in Figure 7.1, there are two full RAM slots (white clips on the ends) and two
empty RAM slots (black clips on the ends). The different colored clips are signifi cant; the
RAM slots with the same color clips must be populated with identical DIMMs. On some
motherboards, the slots are different colors.
FIGURE 7.1
RAM slots on a desktop PC motherboard
Some notebook computers have some of their RAM permanently built into the
motherboard, so you can't replace it (or at least not easily). For example, you may have a
notebook PC that has 4 GB of RAM in total—2 GB built in and 2 GB on a SODIMM in
an expansion slot. If you want to upgrade this PC's RAM to 6 GB, for example, you can't
do anything with the 2 GB on the motherboard, and the single RAM expansion slot is
already full, so you need to remove the 2 GB in the expansion slot and replace it with a 4
GB SODIMM. You can open the computer's case and check the RAM slots, or you can use
a software utility that tells you the status of each slot.
It's also very important to buy the right type of RAM. As you learned in Chapter 1,
“Core Computer Hardware,” there are many differentiating factors for RAM including
