DRAM

When you open a program, its contents are loaded from storage into DRAM. The CPU and GPU read and rewrite the data in DRAM very quickly as they work. The more DRAM you have, the less the computer stutters when you run several programs at once.

DRAM loses everything it holds when the electricity stops. So data you want to keep for a long time is written separately to storage such as NAND flash. HBM, which sits next to AI chips, stacks DRAM in many layers so that data moves faster.

It is like a classroom blackboard. You can write and erase quickly, but it is wiped once class ends. Anything you want to keep must be copied into a notebook (storage).

The RAM size listed in the specs of a PC or phone, such as how many gigabytes, is the size of its DRAM. As AI servers use more DRAM and HBM, news of DRAM shortages or price rises appears alongside AI news.