Various factors affect the performance of your PC. The central processing unit (CPU), or processor, is important and obvious; it is clear that the faster the CPU, the faster your PC will run. Storage is another, with solid-state drives (SSDs) running much faster than old-school spinning hard drives (HDDs). Another important performance factor is the speed of the RAM. Not all RAM is created equal, and some are much faster than others. The difference won't be apparent to the typical user who primarily browses the web, but if you're a gamer or creative professional, RAM speed could be important.

This guide will introduce you to the idea of RAM speed and provide a basic overview of how it affects PC performance.

RAM parameters
The first and most frequently cited component of RAM speed is its data transfer rate. This is simply the amount of data that RAM can pass to and from your CPU. Today, most RAM is called Double Data Rate (DDR) RAM with a number after the acronym showing its generation. For example, DDR4 for the fourth and current generation. After that, there is a number that designates the speed at which it can run measured in Megahertz (MHz), or millions of cycles per second.

As this guide is being written, RAM speeds range from DDR4-1600 (or 1,600MHz data rate) to DDR4-3200 (or 3,200MHz data rate). You'll also see RAM written as a PC4 spec, which is the data rate multiplied by eight. So DDR4-1600 could also be called PC4-12800, and DDR4-3200 could also be called PC4-25600.

All that said, the faster the data rate, the faster the RAM. That's pretty simple. Modern RAM works best when it's installed in matching pairs of memory modules, that's the "Double Data Rate" part of DDR4. If only one memory module is installed or mismatched modules are used, the data rate will be half the specification. For example, DDR4-3200 would run at only 1,600MHz.

The next component of RAM speed that you can find listed for a memory module is the time or latency rate. This can get extremely complicated, so we won't cover it in detail here, but you'll see numbers formatted as 7-8-8-24 when you read RAM specs. These four numbers refer to the time it takes for the RAM to perform certain functions. Basically, the smaller these numbers are, the faster the RAM will work.



What does it mean for your PC
As we said before, the faster your RAM, the more data that can be fed to and from your CPU, storage, and, in the case of integrated graphics that use system RAM, the graphics processing unit (GPU) every second. A discrete GPU will have its own memory, designated as some generation of video RAM, or VRAM; for example, video RAM currently maxes out at GDDR6.

While RAM speed is important, more RAM is better than faster RAM. If you are setting up your PC and have budget constraints, you may find it economical to buy more RAM that is rated at a slower speed than fewer faster modules. If you're wondering how much RAM to buy, check out our other RAM guide.

Faster RAM is better, but not vital
To emphasize the point, it's always better to have faster components, if you can afford them. But RAM speed is less important to most people than CPU, GPU, and storage performance, and again, more RAM is better than faster RAM. If you're looking to upgrade your PC to make it faster, then spending your money on additional RAM modules, a faster CPU, a more powerful GPU, or an SSD instead of an HDD will give you more bang for your buck.