RAM is the short-term memory for your computer. Whenever you type a word or click on a link to visit a website, your computer’s processor gets the data it needs from RAM.
It’s faster to get to than data stored on hard disks or solid-state drives, which require longer read times.
Random access memory
When you click on a link in a web browser, the series of capacitors and transistors that make up RAM turn on to translate that link into the website you see. Your computer is able to do this because it has quick access to the data in RAM, unlike older storage media that requires a sequence of steps to read or modify information.
This is what makes RAM so fast — it processes data twenty to a hundred times faster than a hard disk. It also keeps your processor from having to access slower secondary storage like a hard drive or solid-state drive when it needs to do something complex.
In terms of performance, the most common path to boosting PC speed is to upgrade the amount of RAM installed. You’ll want to ensure your motherboard supports DIMMs, and that you have the correct type of memory. Memory types will typically display a number that aligns with a specific memory type: 20 for DDR, 24 for DDR2, and 28 for DDR4. You’ll also find CAS latency, which is a measure of the delay between when a CPU requests data from RAM and when it’s sent to it.
DRAM
Every time you play a game or stream a movie, all the data that your computer’s processor needs to run the program gets stored in RAM. It isn’t permanent storage like a hard disk drive or solid-state drive, but RAM resets every time the machine is rebooted.
Each memory cell in DRAM contains a transistor and capacitor that store a bit of information. Each time a bit is read or written, the capacitors lose and gain charge. When the data is needed again, a refresh circuit rewrites the stored bits to the capacitors and recharges them.
SDRAM synchronizes its memory rate with the CPU’s clock speed, so it knows when to respond to a read or write request. This enables much faster transfer rates. The quoted numbers you see for memory performance (the /RAS low to valid data out time) measure how long it takes the chip to open a row, settle the sense amplifiers and deliver the selected column data.
SRAM
Increasing the amount of RAM in your computer can significantly improve its performance. This is because it reduces the number of times the CPU needs to read data from the hard drive, which takes longer than reading data directly from memory. Having enough RAM can also prevent your computer from constantly paging out programs to the hard disk, which slows down operation.
SRAM is a fast volatile memory that does not require constant refreshing like DRAM. It uses a flip-flop circuit to store bits in two states, ‘0’ or ‘1’. This provides high speed, reliability and simplicity while reducing power consumption.
SRAM is often used for a processor cache, small on-chip memory and FIFOs. It is more expensive than DRAM but offers better speed and lower latency. It is a good choice for demanding applications such as video games and Photoshop. A mode register controls the core device operations by regulating the column address strobe’s (CAS) delay, burst type and burst duration.
VRAM
VRAM is a special arrangement of dynamic RAM (DRAM) dedicated to the graphics processing unit. It’s used to store image data that is sent to the display. It’s especially important for computer applications that use complex image textures or polygon-based 3D structures. Examples include video games and 3D design programs.
All types of VRAM are made from dynamic RAM, but some have additional features. For example, GDDR uses a shift register to deliver the next 32KB of data after each clock cycle. This reduces latency and power consumption. It also supports high-resolution textures and a process called MIPmapping. The latter avoids the moire effect-the strange slatted or wavy-looking patterns that result from a high-resolution texture displayed in a lower-resolution space.
Most gaming cards now come with 8 GB of VRAM. This is more than enough to run most modern-era games at medium settings, and it’s also recommended for professional applications like animation and video editing.