Before beginning the procedure for replacing RAM, let’s first discuss its features and characteristics and what purpose it serves.
There are two types of information storage on your computer: primary and secondary. Primary storage is provided by devices referred to as memory or more specifically, Random Access Memory (RAM). Secondary storage is provided by such devices as hard drives, floppy drives, and CD-ROM drives.
There are distinct differences between primary and secondary storage. For example, secondary storage is also known as permanent storage, since the information stored on these devices is saved in such a way that it is available for later retrieval. You can open an application, create and save a document, turn your computer off, and be able to retrieve that document at a later time. That is, when power is removed from the device, the information does not disappear. This is what is often referred to as non-volatile memory.
RAM, on the other hand, is volatile – when power is removed, the contents of the RAM memory chips are lost. We’ve all experienced this at one point or another (has your computer ever locked up just before you saved those latest changes, requiring a reboot or full shutdown?). Because the information in RAM is lost when power is removed, RAM is known as temporary storage.
The advantage that primary storage (RAM) has over secondary storage (hard drive) is that it is much faster. There are a few reasons for this. One is that RAM modules, which plug directly into the motherboard, are purely electronic devices. There are no moving parts. Electromechanical devices such as hard drives and CD-ROMs, with their motors, spinning platters, read-write heads, and so forth, take much longer for the CPU to access.
Secondly, because RAM is simply plugged into the motherboard, it is much closer to the CPU than secondary storage devices, which are mounted to the case and connected to the motherboard via an awkward and sometimes lengthy cabling system.
Furthermore, the communications bus for RAM modules is much wider than that of a secondary storage device, meaning that it can move a lot more data in one fell swoop than a secondary storage device is capable of.
So in a nutshell, here’s what happens. When you run a program such as a word processor, the computer pulls the executable file from the hard drive and loads it into RAM, where processing operations are faster. Some additional support files are also loaded, such as DLL (dynamic link library) files, which are shared pieces of code used by multiple applications. The data file you want to work on is also loaded.
Remember also that most computer users have multiple applications open simultaneously. In addition to the word processor, you may also have opened an email program, a graphics editing program (e.g. Paint or Photoshop), and several Internet browser windows.
Modern software applications are very large and complex programs, making them very ‘memory-hungry’. And many websites these days are multimedia in nature, incorporating not just text, but graphics, sound, and video – all of which take up a lot of space in memory. The operating system itself is also loaded into memory, which also takes up a fair amount of space.
When the amount of space needed in RAM for all the open programs exceeds the space available, a ‘swap file’ is created on the hard drive, and information is shuttled back and forth between RAM and the hard drive. This process is managed by a ‘virtual memory manager’, which may notice, for example, that you haven’t used your email program for awhile, and so the email program is swapped out to the hard drive to make room for another program you want to open. This swapping out of information back and forth between RAM and the hard drive can cause a noticeable delay.
So one of the major reasons for adding or upgrading RAM to your computer is to speed up operations. The other reason would be if one of the RAM modules has failed. Either way, there are some technical issues that must be taken into consideration.
First of all, it’s helpful to know how much RAM is installed in your computer. There are a couple of ways you can find out. The easiest way is through Control Panel.
Here’s how to check In Windows XP:
And in Windows Vista:
There are several different kinds of RAM, including the older SDR (single data rate) SDRAM (synchronous dynamic random access memory) found on computers prior to 2002, and DDR (double data rate) SDRAM, which became mainstream around 2002. DDR2-based systems hit the market in 2004, and this type of RAM is able to operate at faster bus speeds.