Apple Silicon's unified memory as it relates to Intel Macs with discreet GPUs

[Hexley]

All M1 Macs with iGPU have the unified memory architecture in place that follows a specific Apple standard.

This is a straightforward replacement of the Intel chips that also have iGPUs that share one pool of memory and no discreet GPU.

So how will we be treating unified memory as it applies to higher-end Apple Silicon Macs that will be replacing Intel Macs with separate system memory and discreet GPU memory?

Example

2020 iMac Core i9 has a base 8GB system memory. I can BTO it to have 16GB discreet GPU memory..

Does this mean that I should configure my 2021 iMac "M1X" with 24GB unified memory to get a similar effect?

If I intended to have 32GB system memory and 16GB GPU memory on Intel does it mean should target 48GB unified memory?

Although I am partial to buying the base model of the largest screen iMac redesign I still want to have a Mac that would last me from 2027-2029 making unified memory selection somewhat of a nuisance

 

[leman]

So how will we be treating unified memory as it applies to higher-end Apple Silicon Macs that will be replacing Intel Macs with separate system memory and discreet GPU memory?

Exactly the same way as M1 works now

If I intended to have 32GB system memory and 16GB GPU memory on Intel does it mean should target 48GB unified memory?

No. Having 32GB system RAM and 16GB GPU RAM does not give you total of 48GB of RAM on your system — it's still 32GB RAM. Relationship between system RAM and GPU RAM is complicated. The simplest (and not altogether inaccurate) way to think of video RAM is simply as the maximal size of a problem that a GPU can solve. If you don't have enough video RAM for a problem, you will suffer severe performance penalties.

Apple's unified memory radically simplifies all this. You don't need to care about video memory at all. Returning to your example, I would choose 32GB of unified RAM.

Although I am partial to buying the base model of the largest screen iMac redesign I still want to have a Mac that would last me from 2027-2029 making unified memory selection somewhat of a nuisance

Why is it a nuisance? You just buy as much RAM as you think you need. There is no GPU RAM to concern yourself with.