CompTIA A+ Certification All-in-One Exam Guide

read or hear about by whatever memory, you need to know whether that
person is talking about the DRAM width or the module width. When the
CPU needs certain bytes of data, it requests those bytes via the address bus.
The CPU does not know the physical location of the RAM that stores that
data, nor the physical makeup of the RAM—such as how many DRAM chips
work together to provide the 64-bit-wide memory rows. The MCC keeps
track of this and just gives the CPU whichever bytes it requests (see Figure 4-
8).
Figure 4-8 The MCC knows the real location of the DRAM.
Consumer RAM
If modern DRAM modules come in sizes much wider than a byte, why do
people still use the word “byte” to describe how much DRAM they have?
Convention. Habit. Rather than using a label that describes the electronic
structure of RAM, common usage describes the total capacity of RAM on a
stick in bytes. John has a single 8-GB stick of RAM on his motherboard, for
example, and Sally has two 4-GB sticks. Both systems have a total of 8 GB
of system RAM. That’s what your clients care about. Having enough RAM
makes their systems snappy and stable; not enough RAM means their
systems run poorly. As a tech, you need to know more, of course, to pick the
right RAM for many different types of computers.
Types of RAM