Ultimate RAM buyer's guide for Windows PC users

be quiet! Pure Base 500DX
be quiet! Pure Base 500DX (Image credit: Rich Edmonds / Windows Central)

It's well known that you need RAM installed inside your PC and it needs to be as fast as your CPU and motherboard will support, but what exactly is RAM, why does your PC actually need it, and when should you upgrade?

Products used in this guide

So, what is RAM?


Source: Rich Edmonds / Windows Central (Image credit: Source: Rich Edmonds / Windows Central)

Random-access memory (or RAM for short) inside your PC is incredibly important. It allows the motherboard (and installed operating system) to quickly store and access data without going through slow (but spacious) storage drives. Even though we're rocking solid-state drives (SSD) these days, RAM modules remain the best option when it comes to accessing data at speed. Yes, even that 4,000MB/s NVMe you just bought is still slower.

But RAM is only meant to store data when it is needed — the process of opening a program is essentially that of copying the files from storage to available memory. You can think of it like a desk: you store papers and tools in the drawers, but when you're going to need something like a stapler and a folder of bank statements, you take them out of the drawer and put them on the desk until you are done and put them away. It's faster and easier to just keep the stapler out for as long as you need it than to put it back in the drawer after each time you use it.

Your PC will use available RAM to run Windows and programs you're using, so the amount you'll need will vary at any given time. You can quickly check how much RAM is being used by opening the Windows Task Manager, which can also show you how much RAM is free and how much is being used by each individual program. Don't feel like you have to immediately purchase more RAM if your system is using a fair amount (say 75%). Unless you're frequently maxing out the available RAM, it'd just be a waste. Remember: unused RAM is wasted RAM.

But should your system be using all available RAM, the hard drive will be used as a backup to store and read data and emulate RAM — a "page file" or "virtual memory." While this enables you to do more even with limited RAM, even a speedy SSD is significantly slower than your RAM, and your computer's overall speed will suffer when it has to use your storage drive as an overflow. In the desk metaphor, you've got too much on your desk at once, and you're having to constantly swap positions of stuff between the surface and the drawer to keep going — you can have more going on, but it's slow, cumbersome, and wears on your drawers. If this is happening frequently, more RAM may be in order.

When to upgrade RAM


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If having close to all your RAM being used by the system is OK, why and when should you upgrade and install more? The recommended amount of RAM for Windows 10 is 8GB, which allows for some degree of multitasking and light gaming. You shouldn't encounter any issue with that amount of RAM unless you're hammering the PC with massive programs like Adobe Photoshop, Premiere Pro, and others on a frequent and simultaneous basis.

But if you hit the ceiling when the performance takes a fall, and you simply cannot push the system further than it's capable of going, you more than likely need to add some more RAM. First, we need to figure out just how much RAM you have, what configuration (or formation) the modules are in, as well as other details like RAM type and clock speed.

The easiest way to check is to download a free tool like Speccy (opens in new tab) that will be able to tell you all of this. The components themselves usually come in sizes of 1GB, 2GB, 4GB, 8GB, and 16GB. These can be DDR, DDR2, DDR3, or even DDR4, depending on what your motherboard and CPU supports.

Acer Aspire 5

Source: Windows Central (Image credit: Source: Windows Central)

DDR stands for double data rate, with DDR4 being the latest and greatest. These modules are not interchangeable. For instance, DDR4 RAM will not work on a motherboard that only supports DDR3. There are rare occasions where a motherboard can sport a hybrid configuration of slots that can take multiple generations. Another way to check what RAM your PC supports is to check the manual for the motherboard, or even look up the model of the board on the manufacturer's website.

What you need to have noted down to purchase RAM is the DDR type, maximum speed, slots, and capacity supported by the motherboard. If the PC or motherboard is from within the past few years, it's more than likely going to be DDR4.

Crucial RAM Tool

Crucial has a handy tool that can check what RAM a specific laptop or desktop PC model supports and recommend upgrades. This is handy if you're not familiar with PC building, don't understand what RAM you need, or just want to have an automated system do all the leg work. The only issue with the Crucial tool is you're locked into the company's offerings. You'll likely want to go elsewhere to take advantage of other deals.

Check out Crucial's RAM tool

Speed and latency


Source: Rich Edmonds / Windows Central (Image credit: Source: Rich Edmonds / Windows Central)

Breaking down RAM classification is rather straightforward. DDR4 is simply a type of synchronous dynamic random-access memory (SDRAM) and is the latest standard available, succeeding DDR3. This allows for improvements like increased bandwidth, speeds, lower latency, and voltage requirements. 3200MHz is the clock speed of the RAM module, and the CAS 15 figure is the latency score.

All together, you'll see the following in RAM listings: DDR4 3200MHz CAS 15.

Using our walkthrough above, we can determine that this module is compatible with the latest motherboards and processors (that support DDR4), is rated at a speed of 3200MHz, and has a latency score of 15. One more thing to watch out for when looking at RAM is the clock speed and latency. With RAM, speed is everything. The latency is essentially the delay between your computer asking the RAM to load a file, while the clock speed is how fast that action will happen.

If you need to buy RAM

Thermaltake RAM Computex 2019

Source: Rich Edmonds / Windows Central (Image credit: Source: Rich Edmonds / Windows Central)

Choosing the best DDR4 RAM for your PC depends on what your motherboard and CPU will support. The majority of motherboards and CPU will work well with DDR4 RAM clocked at 3200MHz, especially if you're building a new PC right now. We've rounded up some of our favorite RAM kits that'll help you create quite the workstation.

Check out our DDR4 RAM recommendations

The lower the latency and the higher the clock speed, the better. As with most things, the better versions are the more expensive ones. Don't feel that you must go for the best RAM if you're not doing a lot of heavy work with your PC. For most case scenarios, any RAM that is supported by your motherboard will do just fine.

The sweet spot for most PC builds is 3200MHz RAM.

Installing RAM


Source: Rich Edmonds / Windows Central (Image credit: Source: Rich Edmonds / Windows Central)

RAM can be installed in various configurations, depending on the motherboard. Modules can be installed in single, dual, and quad-channel. You can find some instances where motherboards can take anywhere up to eight sticks of RAM, making for quite the powerful rig. Depending on the RAM you purchased, you'll need to install the modules in corresponding slots. The motherboard and manual will show you which slots are paired.

For example, if you purchased two 8GB modules (part of a 16GB kit), these will need to be installed in the correct labeled slots to activate dual-channel support, while a single 8GB module can be thrown into a single slot and you're good to go. Before you do absolutely anything when it comes to installing RAM, you need to ensure the system is powered off and take appropriate anti-static measures. In general, though, you'll want all of your RAM to match in size and speed for optimal performance.

Once you've installed the new RAM, you need to hop into your motherboard Basic Input Output System (BIOS) — basically an admin panel of sorts (usually activated during boot by pressing DEL key) — to ensure it's reading the modules correctly. Cross-reference frequency, capacity, and other values between what you see on the screen and what's on the RAM packaging. You can figure out how to access the BIOS at boot by checking your motherboard manual.

The same goes for laptops and prebuilt PC systems, though limitations may be in place. With new RAM installed, you should be able to enjoy smoother gameplay, increased productivity, and multitasking.

Rich Edmonds
Senior Editor, PC Build

Rich Edmonds was formerly a Senior Editor of PC hardware at Windows Central, covering everything related to PC components and NAS. He's been involved in technology for more than a decade and knows a thing or two about the magic inside a PC chassis. You can follow him on Twitter at @RichEdmonds.

  • I upgraded mine when newegg had a sale. 32GBs that I'll probably never use, but I got a great deal!!!!!
  • I have 32GB too, bit of overkill but it's there if I need it. It also means I can run a Virtual machine with 8GB of RAM and not have any resource issues
  • When was 4 GB enough? Not really extremely long ago. I'm sure that we will see a minumum ram needed recommendation of 16 GB coming and 32 as well, it's just a matter of time.
  • Better purchase same RAM sticks. If the voltage and latency don't match, you may be in deep trouble.
  • It is always wise to purchase identical sticks of RAM, however, most motherboards now allow you to modify/adjust the voltage, latency and frequency of your RAM. So if you are piiecing a PC together of spare parts and the motherboard isn't something that belongs in a museum you should be fine. Older motherboards may not allow you to adjust the latency and frequency manually, most of them will default to the slower stick anyways. Otherwise if you are building new its always best practice to purchase identical RAM, as Pallav pretty much said, stability. You will save yourself from possible headaches and frustration.
  • The desk metaphor is a good example to explain RAM to non techies. 👍🏻
  • And he should have added that Amount of RAM is like desk space. The more the better.
  • Actually the hard drive will always be used by default even if the RAM usage is not maxed out. After I had my first 8GB of RAM I disabled the page file without noticing any side effects. This freed more space on my hard drive and helped boosting the speed of my computer.
  • Good idea if you have enough RAM. But nowadays with SSDs, removing page file doesn't make much difference, unless you are running a regular HDD.
  • Actually with SSDs I'm more inclined to disable the page file as I try to minimize disk writes and prolong the life of the drive. This reminds me, I need to recreate my RAM drive and use it for my browser cache and other temp folders. Maybe Windows Central can write about RAM drives next, which is a cool and useful feature. At least you can make use of all the RAM you are adding.
  • Ssd will last 10 years at 10gb write usage a day, your point is not as valid as it is used to be!
  • You must be doing quite less on your pc. 8 gb is kind of not enough for disabling Paging file. Nit even 16. Maybe a good 32 gb. Will hold the pc in good shape and out of the most of the problems that can occur with paging disabled. As about the ssd. I don't know why are people so scared of loosing this drive. I had an old rig with an old 128 gb ssd on board. The ssd has now about 4 years. It works like new and show no signs of wear. Actually, i bought a new pc and that ssd still functions. This hysteria of loosing an ssd so quickly is actually unfounded. The only thing i do is to keep my files on a good old mechanical drive, or yeah, on two.
  • Maybe you are right about SSDs, but for the page file I have been living without it for 4 years now and doing perfectly fine with 8 GB of RAM, even playing big games like Skyrim. Now I am still on Windows 7 which probably uses less memory resources than later systems.
  • 32GB of RAM and no page file here either
  • Why purchase more ram when you can just download more ram. xD
  • PS: Up to Skylake/Kaby Lake, RAM speeds did not matter THAT much for gaming. But Sky/Kaby profit dramatically for high speed DDR4 ram, that means 3200+.
  • I am adding either 16 or 32 gb of ram to my new dell inspiron 13. Should be a great upgrade...and also the 1 tb SSD.
  • You seem like you're aiming this article at people who know very little about PCs and would never have upgraded or touched the inside of a PC.  Yet with that in mind you didn't mention the notches on the RAM, something very simple which I've seen people completely miss to the extent that they actually damaged their RAM trying to fit it the wrong way.  Also you have no pictures of you actually installing the RAM, something that might be of use to people who have never done this before.  Finally, you forgot about height.  for example those lovely RipJaws you have won't fit under my CPU cooler, however the set of Corsair RAM I have does fit. 
  • Because writing an article based on everyones PC configuration, CPU cooler, case size, type of PSU and GPU installed would be about a million pages long. If you are unable to look at an object and see a pattern to properly fit it you must have been that kid that kept trying to force the square peg in the triangular hole. Yes I do realize people are that stupid, and I don't understand how, but they are. However, I do agree on the lack of content/images on actually installing RAM for first timers.
  • That's the problem though isn't it? People who are first time RAM users might not notice the notch in the slot itself. Slot on the stick itself, maybe.  As I stated, I've seen it happen and that's with people who aren't stupid.  At no point did I ever say write an article covering everyone's PC, mentioning that you need to check if the RAM will physically fit with your cooler, the notch, and a couple of photos do not suddenly make the article explode in length.   The article on the whole is good, but to me it lacks some of the basics.  
  • In no way did I mean my post as an attack on you, re-reading my post I see how my wording caused that, it actually makes me look like a d***. "The article on the whole is good, but to me it lacks some of the basics."
    I agree 100%
    But in a world of instant online knowledge videos are abundant, and accessible from multiple devices. Perhaps they just wanted to reduce redundancy? I don't know.
  • Doubled my RAM on my all-in-one the other day to 8GB, I'm no expert with computers but it was the only thing I could see that might help my PC with some of it's struggles. It's made a good difference, nothing wow but worth the small cost for an extra 4GB.
    That little modification may not be like the work of other guys who build their own super powerful rigs, but for a little moment I felt pretty damn clever.
  • **** RAM and have SSD .
    And see your computer high
  • Crucial RAM is all I will ever buy
  • I see nothing noteworthy in here. No talk about the actually new instance where RAM has shown to be a big deal--overclocking and peak speed on Ryzen. Literally the biggest thing to consider when buying RAM right now, and nothing about it. How is this guide "ultimate?"
  • Note that with the Creators Update the Edge browser has improved security by running more of a web page's code in the tab instead of in the general Edge environment. My experience is that by opening multiple tabs with 4 GB your device bogs down, while 8 GB will do fine. So, using a less secure browser will do if you cannot afford the RAM upgrade.
  • Updated and given no better information. No explanation of where/why you should really worry about RAM speeds. Ryzen still loves fast RAM, to the point of basically demanding it. No metion how using an APU, or something like Raven Ridge, is likely to require more RAM (since there is no VRAM). No mention of using a Qualified Vendor List (QVL) to ensure the RAM you pay for will perform as you expect on the board you get. Very poor quide.
  • You think "RAM prices are crazy now"??? $200 for 16GB? I remember when 16KB - yes 16 kilobytes - was $200. At that pricing, 16GB would've been $200,000,000. The price of RAM has continually dropped over the last 60 years, and capacities have gone up. In 5 years 64GB will be $200, and THAT will be "crazy RAM prices" too.
  • Dear author,
    the following linked text is no longer a valid URL for the tool: "Check out Crucial's RAM tool" I found this https://www.crucial.com/products/memory/memory-buying-guide
    maybe it's the right one?
  • I see you updated the link, using the same as the one I suggested. You're welcome :)