What does RAM do in a computer, and how does it actually impact the various workloads you’ll be running on your PC?
I’ll be answering these questions and more today, and by the end of this article, you should have a solid understanding of what RAM is and what it actually does.
I’ll also address some other RAM-related questions, including what DDR5 RAM does and what makes VRAM different from RAM.
But enough introductions, let’s get right into the meat of it:
What is RAM?
RAM, or Random Access Memory, is the primary form of memory used by computers and smart devices.
The purpose of RAM is to hold everything being run by the processor in active, high-speed memory.
RAM is so closely tied to the CPU and what it does that it’s always kept in close proximity to the CPU through the motherboard to enable rapid communication between the two.
Compared to storage drives like HDDs and SSDs (which have sometimes been somewhat deceptively referred to as “memory” as well), RAM is the dynamic and active memory of your PC.
Storage is also referred to as “static memory” in this context since it’s only periodically read to and written from rather than actively being used by the CPU.
In the context of modern desktop PCs and laptops, RAM comes in the two most popular forms of “DIMM”s or “SO-DIMM”s.
SO-DIMM is a smaller version for laptops, and the main DIMM (Dual In-Line Memory Module) is the form factor used across various generations of DDR RAM and used in Desktop PCs.
DDR RAM, also called Double Data Rate RAM, refers to RAM with the ability to double its effective data-rate when paired with an identical RAM stick running at the same frequency.
The advertised frequency will match this doubled data rate, but the real frequency remains at half that number running on each stick.
What does RAM do in a Computer?
Think of RAM as a countertop for preparing and cooking food and your storage like a pantry.
Everything your PC does is going to be taken from that pantry (storage) first, but it needs to be placed closer to where the action / cooking is (the countertop) so you don’t have to run across the kitchen anytime you need an ingredient.
This speeds everything up. But just like most kitchens will have much more storage in your pantry than on your countertop your PC storage will be much bigger than your RAM.
Your CPU and your RAM are integral to the functioning of everything you do on your PC, but oftentimes the impact of RAM will look minimal on a surface level, especially boosting specs like RAM speed and RAM latency,
Below, I’m going to dive into RAM capacity (the main high-impact RAM spec) before diving into how RAM and its various specs can impact different workloads. This will demystify what it is that RAM actually does in your computer, but the impact is going to change depending on your workload.
What does adding RAM do? RAM Capacity Explained
If you’re having RAM-performance-related issues, you’re most likely dealing with a RAM capacity bottleneck.
The performance issue that is introduced in every application by running out of RAM space is being forced to rely on a paging file for memory management.
Because storage drives, even speedy SSDs, are far slower than your dedicated RAM, being forced to use paging files for memory management will result in a significant performance deficit.
To avoid this issue, the best workaround is simply adding more RAM.
This is why upgrading RAM is always one of the first recommendations when it comes to upgrades– not only is it easy but many performance issues incurred from heavy multitasking can be fixed by simply not being forced to use the paging file.
If you aren’t sure how much RAM you need for a given workload, don’t worry: I’ll be giving you some helpful pointers on RAM capacity per workload moving further into this article.
For now, the basic understanding to walk away with concerning adding more RAM is this:
- Adding more RAM will prevent performance issues related to running out of RAM.
Usually, this means being forced to rely on the drive-based paging file, which results in a slowdown- even for relatively lightweight applications like web browsers.
- Adding more RAM will also prevent outright crashes related to running out of RAM.
This is less likely in general but can happen in certain heavy-duty applications, especially editing or rendering software that can’t make effective use of a paging file.
Sometimes running out of memory can force an operating-system-level crash, too, in the form of a Blue Screen (BSOD).
What does RAM do for Video Editing?
When it comes to video editing, RAM is primarily used for holding active project files, footage, and cached timelines and effects in memory. Having fast and a good amount of RAM enables much smoother video editing and faster render times.
The more your project files can be held in active PC memory, the smoother your performance will be.
Even if you have a high-speed SSD (which will definitely help compensate for when you run out of RAM in bigger projects), RAM is still a much faster cache for editing software to be reading from in real-time.
So, RAM is a pretty big deal for video editing!
It may not have much of an impact on your final render times (which will largely be CPU-bottlenecked, also GPU if you’re using GPU acceleration), but having enough RAM for your video files will make for a far smoother experience working on the editing timeline.
Having SSD storage as a backup instead of an HDD will also help keep things smooth.
Video editing favors high-capacity, low-latency RAM for a smoother workflow and editing experience. The specific capacity you might be looking for will depend on the quality of video files you’re working with and the scale of your video project, though.
As a general baseline, I would start with 16GB for editing 1080p or 1440p footage and move up to 32 GB and higher as you begin editing with 4K or working with much larger video projects (think 20+ minutes).
For more specific details on RAM capacity for your video editing workloads, give Alex’s guide a scan!
What does RAM do for Gaming?
Gaming is actually one of those tasks that can put RAM through its paces- not just in capacity, but also in speed and latency.
The extent to which games can put your RAM or components like your CPU or GPU through the wringer will depend on the specific game’s engine and scope, of course, but there’s still general wisdom to apply here.
First and foremost, RAM capacity is something of a big deal for games, especially modern games with large open worlds.
Obviously, your video card and its VRAM play a great deal in things like this too (more on that in Follow-Up Questions), but your CPU and RAM will be hard at work in any given title managing game logic calculations.
A little-known fact about gaming performance on a PC is that your CPU will always determine your maximum possible in-game framerate, regardless of GPU upgrades or changes to graphical settings/resolution.
While those other elements can certainly reduce or improve the framerate, your CPU is the “brains” of the operation needed to push game calculations and data to the GPU before your GPU gets to render anything.
This is why high-end CPUs are necessary for achieving high refresh rates in intensive modern titles.
RAM factors into this, too. Beyond just needing more capacity for modern games (8-16 GB should be enough RAM for just about any game, fortunately), gaming performance is also impacted by seemingly-secondary factors like RAM speed and RAM latency.
The impact made by these factors isn’t as easy to track, especially in older games that aren’t made to utilize fast RAM, but it’s still significant.
The biggest benefit you’ll see across all games from boosting RAM speed is an increase in minimum framerates, also called 1% and .1% lows.
Give a modern game engine an intensive enough scene (especially with lots of active players/entities) and it will drop frames trying to keep up with it all, even if you have a strong GPU.
Faster RAM won’t eliminate these dropped frames, but it lessens their severity.
For example, the difference between dipping to 40 FPS from a steady 100 FPS to dipping to 60 or 70 FPS instead. The more dips like that are reduced, the better the frame-time consistency and perceived fluidity of the experience.
Depending on the game engine, improving RAM speed and latency can also result in improvements to the average in-game framerate.
With some titles, this can mean as much as a ~20% boost in average frames…but for others, the difference can be minimal if it exists at all. Check out my RAM Frequency Guide for more details on that.
What does RAM do for Streaming?
For live-streaming purposes, RAM is fairly important.
Since you’re streaming footage to the Internet in real-time, your CPU and RAM are going to be the most responsible for managing that footage.
Your GPU, if its encoder is being used for live-streaming, may also be taxed by this process, but generally, the CPU and RAM demands will be the heaviest. So, what do you need to know?
First, it’s important to clarify the kind of streaming setup you have. If you’re streaming non-real-time rendered footage (ie from a camera or a pre-recorded video), you can pretty easily get away with 8 GB of decent RAM.
However, if you’re like most live streamers on Twitch and are also streaming games, 8 GB of RAM will only be enough for a secondary PC. That is, a secondary PC that is streaming footage from the first PC, focused entirely on games.
If you’re doing your streaming and gaming on the same PC, I’d consider the baseline RAM requirement to start around 16GB (for lighter games/eSports titles) but trend toward 32 GB and higher for intensive modern games, which have higher RAM requirements.
While RAM speed and latency are less likely to have a direct impact on this particular workload, they’re still very important to consider if you’re gaming on the same PC: see the previous section.
What does RAM do for Professional Rendering, CAD, and Heavy-Duty Workloads?
The RAM needed for truly heavy-duty professional workloads, like 3D modeling, sculpting, animation, texturing, or CAD, can range anywhere from 32 GB to 64 GB. If we add compositing (e.g. AE, Nuke, Fusion) into the mix you can even double that amount.
That’s because these workloads, besides needing a lot of raw space available in memory for project files and assets, also have a lot of complex calculations that need to be managed by your CPU as fast as possible.
With something as intensive as high-fidelity fluid simulation, or multi-layer-exr 32bit After Effects compositing, the RAM requirements are so steep that a whopping 64 GB of RAM becomes a requirement for acceptable performance.
If you’re doing truly high-end work that requires a high-end CPU, 32-64 GB of RAM is strongly recommended for accelerating these workloads with minimal bottlenecking.
Other factors can impact your performance in these workloads too, of course- besides RAM and CPU, high-end workloads that support GPU acceleration (also with multiple GPUs) will also be dependent on powerful GPUs with lots of excess VRAM.
When it comes to individual PC use, 64 GB of RAM is about where things begin to peter off in terms of finding viable uses.
However, you may still be inclined to opt for higher amounts of RAM when using server or HEDT (Intel Extreme, AMD Threadripper Pro) processors. Especially for a server, lots of extra RAM is needed for managing large amounts of data being pushed through different connections simultaneously.
For more on specific RAM requirements for a wider variety of professional workloads, and how RAM capacity impacts those workloads, I highly recommend Alex’s RAM Capacity Guide.
The 32-64 GB rule outlined above should largely hold true when it comes to capacity, though!
What does DDR5 RAM do?
If you’ve read through this article, you may be wondering where the explanations for DDR3, DDR4, and DDR5 RAM are.
While I mentioned Double Data Rate RAM as a concept at the beginning, I didn’t talk about the various generations of DDR RAM.
While their basic underlying functionality is the same, each generation sees significant boosts in both DRAM frequency and data-rate.
So, DDR5 at the moment is pretty much just a faster version of DDR4.
The pricing is even beginning to dip closer to DDR4 levels, though early DDR5 sticks are being manufactured with much higher latencies than DDR4 sticks.
Not enough to make them worse than DDR4 in most scenarios, but enough that I’m confident that as DDR5 latency is improved, DDR5 performance improvements will also scale in those latency-sensitive workloads.
For some up-to-date performance numbers on DDR5 across various workloads, check out the performance sections of my RAM Frequency Guide. I discuss the improvements introduced by DDR5 in those sections, as well as the caveats that come with them in more detail.
What does Dual-Channel RAM do?
Dual-Channel RAM enables DDR (Double Data Rate) RAM to do its…well, double data rate. Specifically, this “doubling” is being done based on the matching Megahertz and Megatransfers of a single RAM stick.
When an additional RAM stick is added, this allows both RAM sticks to run in a Dual-Channel configuration, which doesn’t actually increase Megahertz despite marketing but does double Megatransfers…or, data rate.
Depending on the workload, enabling Dual-Channel RAM will either result in a moderate improvement to performance or one marginal enough it may not even be noticeable.
For more on which workloads are impacted most by Dual-Channel configurations, head over to my Single Channel vs Dual Channel article.
You can also read more on the distinction between Megahertz (frequency) and Megatransfers (data rate) in Jerry’s article if you’re curious.
How do I make sure my RAM runs at full speed?
In order to maximize your RAM speed, you’ll want to make sure you’re running in a Dual or Quad-Channel configuration.
When it comes to RAM speed, by default RAM sticks will be capped to run at the minimum standard of that generation.
In order to actually achieve higher numbers advertised on the box, you need to enable the embedded XMP profiles stored inside that RAM, and the only way to do this is by enabling it in the BIOs.
You can also manually adjust your RAM frequency, timings, and voltages, but XMP is a much more accessible solution, and the recommended one in most scenarios.
What makes VRAM different from RAM?
Finally, let’s talk about what makes VRAM different from RAM.
I’ve mentioned it a few times in this article, and there’s definitely a lot of crossover between how VRAM and RAM are used by your PC.
Over in the world of current-gen gaming consoles, VRAM is actually being used as RAM, but that wouldn’t work in a PC environment.
Setups like that are only possible on standardized hardware and operating systems, like the ones offered by the PS5 or Xbox Series X.
VRAM stands for “Video RAM”, and it’s pretty much exactly what it sounds like. It’s a RAM but used exclusively by your GPU.
With discrete GPUs, this VRAM is attached directly to the graphics card.
VRAM also comes in different standards and form factors than standard desktop RAM, namely GDDR and HBM.
With CPU-integrated GPUs, however, standard RAM can be allocated for use as VRAM. Specialized VRAM is faster than desktop RAM used as VRAM, though.
For a more detailed rundown on VRAM vs RAM and how they impact different workloads, check out my VRAM vs RAM guide!
Over to You
And that’s it, at least for now! I hope that this article helped illuminate the actual purpose of RAM inside your PC across the various workloads that you’ll be taking it with.
More RAM is better, for sure, but there are more questions to consider than just how much you can stuff into your PC. I hope this cleared those up!
For now, leave a comment below or in the forums if you need any further assistance- we at CGDirector will be happy to help you. Until then or until next time, take care- and don’t forget: you can’t actually download more RAM.