RAM is the heart of your computer. Without it, everything from browsing the web to saving a document would take significantly longer.
As your computer performs tasks, it pulls data from RAM and stores it on non-volatile disks. The difference is that RAM needs constant power to stay alive and disks retain their content even when the system is turned off.
Random Access Memory
Unlike hard disk drives, which use read/write heads to access data in a fixed sequence, RAM lets you quickly move bits of information around the circuit board at will. This is why it’s called random access memory, and why it’s faster than other types of storage.
RAM acts as your computer’s short-term memory, keeping all of the necessary data handy so that the CPU can quickly run applications and open files. It also helps your laptop or desktop stay responsive to your every whim, from clicking a link on a website to jumping in the middle of a video game. Without enough fast RAM, your computer will start to lag—you might even see a spinning wheel cursor as the CPU struggles to retrieve information from slow storage devices like the hard drive. The best way to increase your computer’s speed and performance is to add more RAM, which you can do at home or by taking it to an expert.
Memory Density
Memory density refers to how much information can be stored within a physical volume of a memory device. In digital computers, this information is represented in the form of binary digits, which are processed by logic gates. As fabrication methods improve and circuit design changes, memory densities increase.
However, there is a limit to how much information can be stored in a given physical space, called the Bekenstein Bound. This limit cannot be overcome by increasing redundancy or using error-correction code techniques, and it is instead limited by the physical laws that govern how information can be manipulated at atomic levels.
Currently, the leading technology is flash memory, which can store more data than DRAM at a lower cost per bit. PCs typically use SDRAM, a type of flash memory that is synchronized to the clock speed of the CPU. Memory sticks come in several different densities, with high-density modules having fewer chips with more memory each.
Memory Types
ROM, or read-only memory, is non-volatile and holds data even when the computer is powered off. But RAM is volatile, and it loses all stored information when the computer reboots. It’s designed for fast and temporary storage of information the processor needs while the computer is in use.
Whenever you click a link to open a website, the computer transfers that data from RAM into long-term storage on your hard disk. Similarly, when you close and relaunch software, the program opens significantly faster because it has already been loaded into RAM.
The original dynamic RAM, or DRAM, uses capacitors that charge and discharge to store a 1 or a 0. This requires constant power to maintain its state, but it offers higher densities and lower unit costs than static RAM (SRAM). Later versions of this technology, such as Burst Extended Data Out Dynamic RAM (EDO DRAM) and SDRAM, offer increased performance. These days, most computers use DIMM modules with a capacity of 4 or more gigabytes.
Memory Installation
Adding or replacing RAM in your computer is one of the easiest tasks you can do to improve its performance. The key is choosing the right memory that works with your motherboard and determining how much you need.
Some computer manufacturers sell a RAM selection wizard on their websites that you can use to find the type of memory your machine accepts. You can also read your motherboard manual for directions. The physical process of changing out a SIMM or DIMM is relatively simple; you simply slide the card into place until the metal clips on either end snap into place.
Before you open the case to install new RAM, be sure to unplug any power cables and discharge static electricity by touching an unpainted metal surface (such as a screw on the chassis). When you’re ready to begin, be careful when handling RAM modules; they’re typically notched on one end, so they should fit into the slots with the notch lining up with the latch guides.