Like iPhones and iPads, Apple Silicon Macs uses an Apple-designed GPU – something that makes complete sense when you consider how existing iOS devices function. Nevertheless, it may be a cause for some high-end users to pause during the Intel hardware transition process.
Tile-Based Deferred Rendering
You see, while Intel Macs contain Intel, Nvidia, and AMD GPUs, Apple Silicon Macs will use what the company seems fond of calling "Apple Family" GPUs. They use a rendering framework called Tile Based Deferred Rendering (TBDR) that iOS devices already use.
It operates differently from the Immediate Mode rendering method supported by Intel Macs. While the latter immediately renders imaging data to the memory of the device, the former makes further use of the GPU by sorting each element first before sending it to the memory of the device.
What are the benefits that this brings?
The result is that the TBDR rendering provides lower latency, better performance, lower power requirements, and higher bandwidth. The A11 chip and Metal 2 have consolidated this technique.
Current developer-system Macs use the A12 CPU, and Apple is now on track to bring an even more powerful system to the iPhone 12 's intended A14 processor.
It is important to remember that the Mac GPU with Apple Silicon is a member of GPU families and supports both the Mac family and the Apple family of features. In other words, using Apple Silicon and Rosetta, you should still be able to use Intel-based Mac applications.
It’s a System on a Chip (SOC)
The GPU is another distinction between (most) Intel and Apple Silicon Macs. Although Intel systems use discreet GPUs from other manufacturers, Apple Silicon Macs combine processors, co-processors – including video encoders and decoders – with Neural Engine and machine learning accelerators on one chip.
This ensures that graphics resources can be shared more effectively between CPU and GPU without the overhead. It also provides that you can conveniently tweak iOS software to run on Apple Silicon Macs.
Apple Silicon processors also bring high-efficiency audio coding, power management, storage controllers, Protected Enclave, camera processor, and support cryptographic functions for Macs currently using a T2 chip.
As a result, these systems can do much work, all on the processor, for fast performance and improved memory bandwidth, power management, and battery life.
One of the best ways to see the difference this creates is to run a high-performance Apple Arcade game like Oceanhorn on both the iOS and Intel Mac systems. You won't have to wait long before the Mac fan begins making a racket; that won't happen in the future (as long as they run Apple Silicon and the apps are native to Metal).
Apple already makes its own GPU
Apple has been manufacturing its GPU silicon for years. It replaced Imagination's PowerVR tech some time ago, although a new licensing agreement was reached with Imagination.
But having a GPU tech that works fine on an iPhone or an iPad is one thing. Is this going to translate into efficiency advantages for Macs?
Early graphics efficiency tests for the new Apple Silicon indicate that Apple's eight-core A12Z running macOS 11 already surpasses the built-in graphics for both the AMD Ryzen 5 4500U and the Intel Core i7-1065G7 chips. This is exciting, considering the imminent debut of the Apple Silicon A14 chips.
The problem with the strategy is when it comes to third-party GPUs such as Nvidia, AMD, or Intel; Silicon Macs will not support these (at least at the moment). This includes the external GPUs used by MacBook Pro and Mac Pro.
Apple's point may be that the need for such external GPU systems would be mitigated by switching to more efficient home-baked graphics technologies, which may be right.
The company has also committed to launching new Intel-based Macs that will support these external systems during the current transition.
What's up next?
We already know that the Apple Silicon Macs are going to be quick. We now see those performance improvements will apply to graphics systems – and we can speculate that future Macs will be high-performance systems that use less power than before.
How is Apple going to exploit this? Is it going to ditch fans to make thinner Macs? Will it take advantage of the ability to explore a new design language for its PCs? At what point will the iPhone become the Mac that you ever need, given your choice of user interface and access to a larger screen?