There's no universal answer to how much RAM you need in your computer. After all, it depends on what you need to do with your system. However, people often feel they need to upgrade their RAM when they notice it's always nearly running at full utilization. However, nearly full isn't the same as full.

Empty RAM is wasted RAM

Why would you want your RAM to be unused?

The memory in your computer is managed by the operating system, and by and large, it knows what it's doing. Likewise, applications can take advantage of free memory to improve how well they run or respond. If you have lots of free memory, it will be used for caching, preloading, and whatever else your software can use it for. So the mere fact that your memory is nearly full doesn't mean you need more of it. It just means that your software is making the most of the memory you have.

This has diminishing returns, of course. For example, on my 32GB Windows system there's typically 16GB of memory in use while running a few dozen Chrome tabs and other odds and ends in the background, like Spotify or TeamViewer. On my previous 16GB Windows system I ran the exact same workload, but didn't have anywhere near 16GB of memory in use. Likewise, my 8GB M1 MacBook Air runs exactly the same desktop workload as my Windows system, with little to no difference in usability.

The bottom line is that RAM usage isn't a problem, until it's a problem. So how do you know when you've got a RAM shortage?

System slowdown

Stutter st-st-struggles

If your system freezes, hitches, or otherwise goes from being smooth and snappy to running like syrup, that's potentially a sign that your RAM is inadequate. If your CPU usage isn't high, but your disk activity is, it probably means that your computer is forced to swap RAM content with your SSD or hard drive. Thanks to the advent of super-fast SSDs, the performance impact on your system might not be all that noticeable even if you are running out of RAM.

App switching is slow

Multi-tasking through the mud

Apart from system hitching and freezing, slow performance when switching between apps is a key sign your RAM is overly full. Single apps, except for some professional apps like video editors, don't typically use huge chunks of memory, but if you tend to have a ton of apps open, then the ones that have "gone to sleep" might be moved out of RAM if there's no room for them. This means that when you switch apps, it can take a significant amount of time to transition.

The one exception to this, in my opinion, is when you switch to the desktop from a video game, and it takes a long time to load your apps. Modern video games are very memory-hungry, so it's normal on, for example, a 16GB system to experience a slow transition to other apps from a video game. That doesn't necessarily mean you need to upgrade your RAM, it just means that you can't run other apps alongside your game. However, unless you're running streaming software or apps like Discord on a second monitor while you play games, this isn't a big deal, since most people won't be multitasking while actively gaming.

Video game stutter

Yet another reason your games aren't running smoothly

While you want 99% or 100% usage of your GPU while gaming, you don't want those sorts of numbers for memory while you're playing video games. If RAM swapping starts happening in a game and you're forced to make use of virtual memory, you may experience frequent stutters or freezes that aren't related to your CPU or GPU. Incidentally, this also applies to your VRAM on your graphics cards. If you run out, your frame rates will tank and the game will start stuttering.

You can use tools that come with your GPU software to monitor RAM usage while in-game, or on Windows you can use the Xbox Game Bar's performance widget. If you see memory spikes that coincide with these freezes and stutters, then you're running out of physical RAM.

You can address this by lowering settings in the game that have an impact on memory usage, or you can bite the bullet and buy more RAM. However, in most cases, you can trim some minor things to get back in the green without affecting how the game looks or plays too much.

Out of memory crashes

The worst-case scenario

Sometimes, the sign that you've really run out of RAM is a literal error message telling you that you've run out of memory, usually accompanied by the app in question crashing. This only happens when your physical memory and also your virtual memory have both run out completely.

Sometimes this happens because of a glitch, such as a memory leak. However, if it's happening often, and you can't fix it by reducing the number of open apps or increasing your page file size, then the next step is to increase the amount of RAM you have.

You probably have enough RAM

Unless you're experiencing actual performance issues while seeing 100% RAM usage in the monitoring app of your choice, then you're probably good to go with the amount of RAM you have. If an app you want to use recommends more RAM than you have, that's also a reasonable reason to consider installing more. The rest of the time, just don't sweat it!