How much unified memory do I need in my Mac?

One of the biggest impacts of Apple’s shift from Intel to its M-silicon series – Debuting with the M1 In 2020 MacBook Air, MacBook Pro, and Mac mini — Mac and MacBook are faster, more stable and more power efficient. This is all thanks in part to M’s unified memory architecture and system-on-chip design, which changed how processors worked together and how memory was allocated.

The switch to UMA also changed how Apple decided which configuration to choose when purchasing a system. The UMA does not allow for upgradeable memory – the memory is built into the SoC – so it is important to estimate how much you might need over the life of the system and have it up and running at the time of purchase.

How much memory?

All current M4 and M5-based Macs and MacBooks include at least 16GB of memory, which should cover most people’s daily workloads, whether that’s general web browsing, working in office productivity software, programming, or light photo and video editing.

If you’re considering purchasing a used or older M3, keep in mind that these input configurations only include 8GB; More memory means access to the Pro or Max version of previous chips. If you plan to take advantage of Apple Intelligence, you’ll need at least 16GB.

To future-proof your Mac, the best way is to purchase more unified memory if your budget allows. That 16GB of storage may have been sufficient when you purchased it, but you’ll likely notice some slowdowns as the operating system and apps become more demanding or AI-reliant over time. Consider upgrading to 24GB or 32GB if you plan to keep your computer for more than five years or anticipate a major life change that might affect laptop use, such as going to college or switching jobs.

For more advanced tasks, look for a high-end M-series chip like the Pro or Max. These devices currently start with 24GB or 36GB of memory, and their UMA has more bandwidth for more processor-intensive tasks (particularly those that are GPU-intensive), such as 3D modeling, AI development, and machine learning. But given the type of workloads these chipsets are designed for, the core memory may be insufficient. Aim for at least 48GB or 64GB.

If you decide to go up on memory at the time of purchase, you’ll need to budget accordingly since UMA stands for a different SoC instead of just RAM, so it can be more expensive than traditional.

Why UMA?

The unified memory setup is designed to accelerate performance and reduce power usage. Instead of separate, dedicated system memory banks for the CPU and GPU video memory (RAM and VRAM, respectively) used by traditional computing architecture, Apple’s UMA has a single pool of memory shared between the CPU, GPU, and Neural Engine (to handle AI and machine learning tasks), the three processors that make up the M-SOC series. Unlike RAM and VRAM modules, which are inserted into sockets on the motherboard or graphics card, UMAs are soldered onto the SoC.

With dedicated memory, it takes multiple steps to move data from RAM to VRAM (and vice versa) when it needs to be processed by the CPU, NPU, and GPU, which can cause bottlenecks and latency. UMA eliminates extraneous, time-consuming steps, since the processors only store and retrieve from the same cluster. It also allows the system to dynamically allocate memory as necessary for best performance rather than less efficiently allocating fixed amounts to each processor.

This system, combined with the operating system, allows even Macs with a basic amount of memory to do more: the 8GB of memory in the UMA Mac isn’t necessarily less powerful than a traditional 16GB system. Apple also uses memory compression to increase the effective amount available.

If you are or have been an Intel-based Mac user, you may have experienced short battery life, heat buildup, and loud fan noise when taxing the system. UMA helps M Series Macs achieve longer battery life and run cooler than Intel Macs. Fewer components have also allowed Apple to reduce the weight and size of its laptops.

Disadvantages of Apple UMA

UMA design becomes an issue when your workflow or applications start using memory intensively to do concurrent tasks – there is only a limited amount of things available to share at once, which can lead to decreased performance. When there is no memory left to allocate, the system will use virtual memory, switching between RAM and SSD, slowing down overall performance even further.

This doesn’t mean that a basic-spec Mac will become unusable over time. Apple does a good job of optimizing performance for longevity. Although you may notice some slowdown over time, your Mac should still have enough capabilities well into the future.

Not all applications can benefit from the efficiency of UMA if they are not optimized for Apple Silicon. Fortunately, most Mac apps are now available, including memory- and processor-intensive apps like those offered by Adobe. And while Apple’s Rosetta can run Intel-based Mac software on an Apple Silicon Mac, and you can run PC software via an emulator like Parallels, you won’t necessarily get the same performance as native software; You may need to purchase more memory for these applications.

Although a professional-level Mac may offer some performance benefits for demanding applications, it may not be enough for some users. Ultimately, the type of software and user will determine whether a UMA is appropriate. Some power users (engineers, researchers, IT professionals, and special effects artists), as well as gamers and developers, may find the all-in-one design restrictive, especially since Apple’s M series does not support discrete GPUs in addition to its persistent memory.