google搵到24GB答案:
No, LPDDR5 offers up to 50% more RAM density so the standard 8GB becomes 12GB (96Gbit).
The M2 still uses 128-bit memory bandwidth by using two memory modules. That gives you the standard configurations using 2x4GB (8GB), 2x8GB (16GB) and 2x12GB (24GB).
姐係粒M2連接出去兩粒DRAM module個die / channels係無變過,只係嗰兩粒密度增加
咁我諗OS level已經一定任用晒24GB,只係apps未遇過Mac機有24GB呢個scenario?
不過其實Mac Pro 2019係有6 slot,雖然Apple無俾人configd可以自己插6條4GB入去