Technical Terms: GPU

The GPU, or Graphics Processing Unit, is one of the most important components of any computer or device. Macs come with a variety of different GPUs. For many users, the GPU power doesn't matter much, but for anyone working with graphics, video or playing games, the GPU is very important. Some MacBook Pros come with two GPUs and will switch between them to save battery life.
Video Transcript / Captions
Closed captioning for this video is available on YouTube: Technical Terms: GPU.

Here's a term that you may have heard of but may have not given much thought to and you really should think about this if you're in the market for buying a new Mac or actually any computing device. The term is GPU. It stands for, simply, Graphics Processing Unit. Now this is different than the CPU or Central Processing Unit. We usually spend a lot of time thinking about the Central Processing Unit when we're buying a new computer or looking at one and trying to determine how powerful it is. We'll look at the CPU's speed. We'll look at what generation of CPU it is and all that.

But what's equally important, sometimes even more important, is the Graphics Processing Unit. It's used pretty much on all computing devices. So you definitely find it on all the Macs. You'll find it on iPhones, tablets, you know the iPad, and also on game consoles. Really anything that has a display that's a computing device is going to have a GPU as well as a CPU. The GPU is used for a lot of different things. Of course it's used to run the display that you are seeing. So a more powerful GPU would be able to handle more screens or higher density screens. Things like that.

It not only handles 2D graphics, and 2D graphics includes drawing the screen. Whether you're using a word processor or just moving files around you're actually using 2D graphics. Also 3D graphics that are used in games and in some regular apps too actually have 3D graphics in them nowadays. It's also used for encoding and decoding videos. If you're processing a video like an iMovie or Final Cut you're using the GPU. Also if you're just viewing video you're also using the GPU on your computer. It processes large blocks of numbers when it does this. So sometimes it's used for other tasks where there are large blocks of numbers. The CPU will actually task the GPU to do some of this processing even though it doesn't directly involve a display.

Now there are two things to think about when looking at a GPU. One, of course, is the speed and power of it. But also there's memory use. A GPU comes with either Discrete or Integrated memory use. So integrated simply means it's going to use the memory in your computer. So if you have a computer with 8G of memory and you have an integrated GPU that means it might take 1G of that memory and use it to work with graphics. Discrete means that the GPU has its own set of memory. So you may see a GPU that says it has 4GB of memory and that means that it has its own 4G of memory and it's not actually going to use the regular memory when doing things.

Now when you go to look for a new Mac on the Tech Spec page for any Mac on the Apple site you're going to find a listing for graphics and this shows the GPU that comes with that Mac. So, for instance, for the 27 inch iMac's currently you can see that there's a choice of three different GPU's. You can search these GPU's and come up with detail specifications of exactly, you know, how powerful each one is. But you get a general idea by looking and figuring that the 570, 575, and the 580 Radeon Pros are one better than each other. The 575 is better than the 570. The 580 is better than both. You can see that they have 4GB of Vram, video memory, which means that they are Discrete memory devices. They have their own memory which is going to be good and it's going to increase performance in all sorts of ways on the iMacs.

Now if you look at say the 13 inch MacBook Pro you'll see under graphics the Intel Iris Plus Graphics 640 and 655. You can guess that the 655 is a little more powerful but notice that it doesn't show memory. These are integrated graphics meaning that they are going to use integrated memory, part of the memory of your Mac. So if you have 8G of memory some of that is going to be used by the GPU. But if you go to the 15 inch MacBook Pro you can see that you get Radeon Pros there. The 555X and the 560X. You can look those up and if yo0u want the details but you can gather that one is a little more powerful than the other.

But notice that it also includes Intel UHD graphics 630. It looks like there are two GPU's for the 15 inch MacBook Pros. In fact there are. Why are there? I mean there's one that's more powerful, the Radeon, and it's integrated memory, discrete memory for itself. The Intel is going to use regular memory and it's less powerful. Why? Well, because the MacBook, of course, a lot of time runs on battery. The Radeon Pros are going to use more power because they're more powerful. So there's going to be automatic switching. When you're doing something that's not using a lot of graphics and you're on battery power it's going to automatically use the lower power Intel graphic chips and when you're plugged into power and/or using something that requires it, it's going to use the Radeon Pro. So that's kind of a neat thing that you've got there with some of the higher end MacBooks now.

Now you may also be hearing the term GPU with some of the newer Macs in reference to using external GPU's. With Thunderbolt 3 on newer Macs you can actually plug in a device that's actually a GPU. It's an external GPU that can speed up graphics processing. This is commonly done by people that have to handle 3D graphics and video and things like that. So you can look into that. Apple has a great page about that and shows you which devices are supported. There are several for sale right now and you can find out more about that at Apple's site.

Now one thing to note is that for a lot of people the GPU really doesn't matter. If you're going to be just surfing the web, writing emails, maybe doing some word processing, things like that then the Intel integrated GPU's that come with some of the lower end MacBooks and things, they're going to be fine. If you're doing graphics work, doing video editing, and if you're playing games then you are going to be concerned about the GPU. You want to look at that as well as looking at other things like CPU and memory and other features of a Mac when shopping for one.