RAM stores temporary data for quick access by the computer. Like a desk drawer, it holds items you use right now and gets wiped clean when you turn off the computer.
If your PC starts feeling sluggish, check to see how much RAM is installed. If it’s bursting at the seams, it may be time to upgrade.
Random Access Memory
Known as RAM, this is the short-term storage component of a computer. It stores the data your operating system needs to work with now – everything from the website you’re visiting to the movement of your mouse across the screen. It offers lightning-fast access to the bits of information your computer is currently processing, so it works orders of magnitude faster than retrieving data from a hard drive or SSD.
RAM is made of tiny capacitors on a single chip that hold electrical charges. When your operating system calls for information, the chips on a memory stick activate the appropriate capacitors, storing or reading data into or out of a location that has been mapped to a binary address.
RAM is typically sold in sticks that snap into the motherboard slots. RAM that is incompatible with your motherboard and processor won’t fit or function properly, so make sure the spec is right for you before you buy.
Cache Memory
Cache memory acts as a high-speed interconnect and queue between the CPU and main RAM. It takes data and instructions stored at certain memory addresses in RAM, copies them into the cache, and stores a record of the original address (called a tag) that the processor needs to retrieve it.
If the CPU reads from or writes to a location in main memory that isn’t in the cache, it has to resort to the much slower hard drive and RAM, slowing processing down. This is known as a cache miss.
A key design issue is how quickly the cache can get full. This can be influenced by the cache’s mapping technique, which decides whether speed or information search accuracy is prioritized. For example, some caches require that data residing in the L1 cache also be in the L2 cache (strictly inclusive). Other caches use a less-restrictive policy. A typical cache uses a demand paging scheme, which reads the minimum amount from the backing store on every cache miss.
Video RAM
VRAM (Video Random-Access Memory) is a type of RAM that’s used by computer video cards to store image data for computer displays. VRAM is distinct from your main computer RAM, and it’s designed to meet the high performance requirements of graphics-intensive applications, such as 3D rendering software.
When a game loads, all the graphical data for that level is stored in your GPU’s VRAM, which is located on the video card itself. The data is then quickly transferred to your main RAM so your CPU can work with it.
To prevent this slowdown, MoSys developed multibank DRAM (MDRAM), a high-performance form of VRAM that divides memory into 32 kilobyte segments that can be accessed simultaneously. This improves the speed of data transfer and increases overall performance. You can check how much VRAM your video card has by looking at the video settings or by navigating to About This Mac in the Apple menu. Increasing the amount of VRAM will give you better gaming performance.
DRAM
When you click a link to open a website or start a new program, a series of capacitors and transistors (basically switches) in your computer’s RAM turn on and off to give the CPU information it needs. This information can be accessed much faster than data on a hard drive.
When the program you’re using is closed or the computer shuts down, your RAM is emptied and ready to accept new information again. This data will need to be moved from your short-term memory into the long-term storage of your hard drive, which is slower and consumes more power.
Most pc ram is DRAM, but there are different types of it. Some, like PBSRAM (pipeline-burst static RAM) and DDR SDRAM, have internal data paths to allow a single machine cycle to transfer half a word. Other types, such as ECRD and EDO, improve on this by allowing each access to transfer two words. This can reduce latency significantly.