Can unified memory be easily upgraded?
For years, you could buy memory modules, open up a MacBook, iMac, Mac mini and Mac Pro and upgrade its RAM. Then Apple began to restrict such upgrades meaning you could be stuck with the same amount of memory for the entirety of your computer’s lifespan. This is certainly the case with Apple silicon. Since the system RAM is attached to an M-series chip, there is simply no way of removing the memory and replacing it with a higher-capacity module.
It means you have to think carefully about the amount of memory you may require in the future when making your purchase. You can’t change your mind
Unified memory simplifies matters.
It makes Apple silicon Macs more efficient by handling CPU and GPU memory duties centrally. In other words, it brings highbandwidth, low-latency memory into a single pool that the GPU, CPU and Neural Engine can access. Since the processors have access to the same data, there’s no need to constantly copy information from one pool of memory to another, thereby resulting in less movement of data, making computing faster. There are no buses nor any interrupts (the latter being when CPUs are requested to divert their absolute attention to a particular task at the expense of others). In other words, it’s just better.
More dynamic
Since the unified DRAM memory is situated adjacent to the SoC, the data doesn’t have far to travel and that also makes for speedier computing with no bottlenecks. The SoC also draws less power and generates less heat, meaning longer-lasting performance.
There’s also the little matter of Dynamic Caching and what that brings to the party. Introduced with the M3 range of chips, Dynamic Caching makes vast improvements to the GPU’s performance by only allowing the precise amount of local memory needed for a particular task in real time. It makes more efficient use of the available resources and ensures no memory is being wasted. In fact, later down the line. What’s more, unless you decide to stick with the standard lowest-capacity unified memory, this also means you’re beholden to Apple’s custom build prices. And they’re not cheap.
An extra 8GB of unified memory will take an iMac to 16GB yet cost you £200, while adding 32GB of unified memory to a basic Mac Studio (resulting in a 64GB machine) costs £400.
Take a Mac Studio up to 192GB of unified memory and you’re going to prise open your wallet at least a further £1,600! Big money indeed. Of course, you’re also stuck if the RAM fails for any reason. The price of progress, we guess.
Unified memory brings highbandwidth, low-latency memory
M-series chips are said to be so memory efficient, Apple reckons 8GB of unified memory is equivalent to 16GB of regular RAM.
Is that true? Well, Apple’s motivation in suggesting that “8GB on an M3 MacBook Pro is probably analogous to 16GB on other systems,” as Apple vice president of worldwide product marketing Bob Borchers said, comes in response to criticism that the company’s Macs contain too little RAM. Apple also points to the use of memory compression when claiming users can’t directly compare the memory in Mac to that within a PC.
In general, these assertions have weight. Apple silicon Macs perform extremely well and 8GB, if that’s the amount of memory you choose, is more than sufficient for many tasks. But if you’re putting a Mac under intense pressure, perhaps by opening loads of web browser tabs or editing video, then the more memory to hand, the better. It goes to show that, when it comes to memory usage, two plus two can sometimes equal five. But the takeaway here is that unified memory does help Macs to perform better. David Crookes