If you’re shopping for a new graphics card, you must’ve noticed that there’s always a “Memory” spec on the box. Moreover, a single-card model often comes with multiple memory sizes. But why do graphics cards have it if your computer has plenty of RAM?
There are a few reasons why graphics cards don’t rely solely on your system RAM. VRAM is often faster, more easily accessible, has more bandwidth, is easier to optimize to work with, etc.
1. Graphics cards use memory to store data
Your graphics processing unit (GPU) does thousands of calculations every second to display a crystal-clear image on the screen.
All data required to render a frame goes from your primary storage disk to RAM. The CPU recognizes the data is for graphics, so it’s sent to your VRAM. That’s where it sits until it’s required.
Textures are the perfect example of vital graphics data. Without textures, your games would look like a bunch of random geometric shapes with no immersion quality to them.
Everything from grass and stones to various elements of your gun is a texture glued onto a 3D model.
You can think of video game textures as thousands of high-resolution images. Originally stored in the game folder, textures must stay in your VRAM for easy access when required.
Here are a few other examples of data stored in your VRAM:
- Z-buffer (depth)
- Shadow maps
- Vector graphics
2. Rendered frames are stored in the memory
Your GPU takes the data from the Z-buffer, adds shadow maps to it, does all the required shading, etc.
Once a frame is completely finished, it has to go somewhere. Of course, you see it on your screen, but the monitor only displays the image.
The frame is stored within a special part of the graphics card memory called the frame buffer. New frames are constantly overwriting the old ones to achieve a smooth image.
You can even change the number of pre-rendered frames in the graphics card drivers’ settings.
It’s usually only one frame, but setting it to two or three may improve performance in some cases (or make it worse in others).
3. Graphics cards use a special type of fast memory (VRAM)
Video random-access memory (VRAM), in its broadest sense, is similar to your system RAM.
All data stored in VRAM is temporary, so it’s a type of cache used by your GPU to hold large amounts of data required for graphics.
VRAM is usually much faster than traditional RAM.
More importantly, it’s very close to the GPU physically. It’s soldered directly onto the graphics card PCB.
This allows for super-fast data transfer with minimum delays, making high-resolution graphics possible.
VRAM differs in size, speed, and bus width on modern graphics cards.
More VRAM means it can store more data. Faster VRAM allows for faster data transfers and, consequently, better performance.
Lastly, the bus width determines the maximum available bandwidth. Think of it as a chokepoint between your graphics card memory and your GPU.
There’s also a particular type of VRAM called high bandwidth memory (HBM). A stacked layer of memory sits on a controller die that transfers data to the GPU through a silicon layer.
HBM allows for small form factor graphics cards, faster data transfer rates, lower power usage, etc.
Does a graphics card’s memory size matter?
Graphics card memory size matters because it affects the GPU’s performance. Not having enough memory on your card limits the resolution size, textures, shadows, and other settings.
Let’s use a simple analogy to help better understand how graphics cards work. Your GPU is like the engine in a car, and the card memory is the passenger space.
You can only go as fast as the engine, but you can cram in more passengers if you have a larger car. This improves efficiency, meaning you can bring more people with you for the trip.
Similarly, the performance of your GPU affects how much FPS you can get at certain graphics settings.
If you have plenty of VRAM, you can allow the GPU to render frames at a higher resolution, bump up texture quality, increase details, etc.
You’re still restricted by the GPU’s power, though. So, it’s best to look at the graphics card model first, then the VRAM size.
More VRAM means you won’t experience constant stutters when the graphics card loads an asset from your RAM or storage disk.
Assuming your GPU can handle it, you need sufficient VRAM space to bump up the texture settings, and shadows.
Even the most powerful GPU on the market can’t run games smoothly if it doesn’t have enough VRAM to store assets.
How much graphics memory do I need for gaming?
You need a minimum of 4 GB of graphics memory for 1080p gaming. 6 GB is ideal if you want to set texture quality to High or Ultra. For 1440p gaming, 8 GB to 12 GB is sufficient to run games at medium-high settings. 4K gaming requires at least 12 GB of VRAM for decent texture quality.
In general, more VRAM is always better. If we’re talking about the exact GPU model, always aim for the model with more VRAM if the price is similar.
You’ll probably get better FPS and less stutter, and you can set textures to ultra with a minimum performance loss.
If you’re only playing eSports titles, you could even get away with a 2 GB graphics card at 1080p.
But any modern AAA title fills up 2 GB very quickly, and VRAM usage can even go over 6 GB in some instances.
Gaming at 1440p is more demanding because the screen has more pixels. The higher-resolution frame takes up more space inside the frame buffer.
4K resolution is even more demanding. You already need a powerful graphics card to play games at 4K.
If your graphics card comes with less than 10-12 GB of VRAM, don’t consider 4K gaming unless you want to upscale the resolution.
Upscaling allows you to preserve a lot of VRAM space because it uses special textures that look high-resolution.
If you want to game at 8K, you’ll probably need over 20 GB of VRAM to store the enormous frame.
Can you upgrade the graphics card memory?
Graphics card memory cannot be upgraded because it’s soldered onto the PCB. The circuit board design predetermines the maximum amount on a card. If a manufacturer decides to increase the memory size on a card, the memory chip dies are doubled.
Technically, you could desolder all memory chips on your graphics card and replace them with twice the memory.
However, this is very risky, expensive, and difficult.
So, there is no practical way of upgrading the memory of your graphics card.
Soldering the memory onto the PCB allows manufacturers to optimize the data transfer rate between the GPU and the memory chips.
But you shouldn’t concern yourself too much about VRAM size in the first place. AMD and NVIDIA do a lot of careful planning to decide how much VRAM they’ll put onto their graphics cards.
Combining a low-end GPU with a bucketload of VRAM wouldn’t make sense.
The amount of VRAM they can put in is predetermined by the memory bus size.
For example, if a graphics card has eight 512 MB chips to achieve 4 GB of VRAM, the manufacturer must replace the 512 MB chips with a 1 GB unit to upgrade the VRAM to 8 GB.
For this reason, they usually don’t mix and match memory sizes and speeds.
What is shared GPU memory?
Shared GPU memory is virtual memory that’s located on your system RAM. Your card uses shared GPU memory when it runs out of VRAM space to store assets required to process graphics. It is significantly slower than VRAM, only used when necessary.
Ideally, your graphics card will never use shared GPU memory. However, you can easily tell that your card runs on shared GPU memory. As a result, you’ll get visible jitter, textures load very slowly, etc.
You can also turn on the performance metrics in some games or via your graphics card driver to track VRAM usage.
If the VRAM usage is at 100%, your graphics card will start running on shared GPU memory.
Lower the resolution, texture quality, shadow quality, or other settings in that case. As a result, you’ll eliminate stutter and various graphical artifacts.
If you’re running on an integrated graphics card, your computer has no VRAM.
Instead, your GPU is running exclusively on shared GPU memory.
In that case, there isn’t anything that you can do to improve performance aside from overclocking.
Does GPU memory matter?
GPU memory matters because more VRAM allows your graphics card to store high-resolution frames, more detailed textures, and other assets. More GPU memory doesn’t always mean higher FPS, but it allows for a smoother, more consistent experience, especially at high settings.
When buying a new graphics card, pay attention to VRAM size. You don’t want to waste money on more VRAM when you don’t need it because your monitor is 1080p.
On the other hand, not having enough VRAM will seriously affect overall performance. You need enough VRAM to store the outgoing frame and all graphics assets.
If the price between different VRAM sizes isn’t enormous, always go for the one with more VRAM. It’s a way to make your computer more future-proof.
Even if a modern game can’t occupy all the VRAM today, that won’t happen in a few years.
Assets, especially textures, are constantly increasing in size drastically.
GPU Memory vs. RAM
GPU memory, often called VRAM, and system RAM has many things in common. First, they’re both random-access memory, which means you can write and read any data to them.
However, VRAM is often split into several chunks that store different things. For example, frame buffers, depth buffers, shadow maps, textures, mesh, and other assets are all stored in VRAM.
Your system RAM temporarily stores all the data your CPU needs or may need soon. In addition, the programs and files being used are held in RAM.
For example, all Chrome tabs are stored in RAM, allowing lightning-fast switching between tabs.
The GDDR (or HBM) version determines VRAM speed, memory bus width, and frequency. Speaking of frequency, VRAM easily reaches speeds of 10,000 – 15,000 MHz.
RAM is much slower. Clock speeds usually range between 2400 – 6400 MHz, depending on the DDR version and clock speed.
Moreover, the maximum data transfer rate is much higher for VRAM.