Why Don’t Computers Just Use One Type of Memory? 🖥️💿🛠️

Why Don’t Computers Just Use One Type of Memory? 🖥️💿🛠️ with tags hard drive, hard drive, cache memory, storage devices, cpu cache, computer memory, computer science, computer hardware, memory hierarchy, computer engineering, inside a computer, cpu explained, cache, ssd, solid state drive, hdd, hard disk, micron, cloud storage, registers, cache, cache memory, l1, l2, l3, hierarchy, ssds, sata, nvme, hbme, hbm3e, hbm4, how computers work, random access memory, computer memory and storage, computer storage, computer data, data storage, cloud storage

Your computer has over a dozen different memory and storage locations—from CPU registers to DRAM, SSDs and hard drives—and it needs every single one. In this video, you’ll see exactly why.

We're breaking down the entire explanation of the memory hierarchy into three parts.

First, a visual analogy using books and libraries that finally makes the wild tradeoffs in speed, capacity, and cost click.

Second, a nanoscopic tour inside registers, SRAM cache, DRAM, 3D NAND SSDs, and spinning hard drives to see how each one physically stores bits.

Third, the insane memory and storage stack powering modern AI servers, from HBM3E stacks to petabyte-scale NVMe data lakes.

By the end, you'll understand exactly how your computer—and the AI servers training the world's largest models—juggle data across every layer of the hierarchy.

Notes about the content: As our example computer, we’re using a typical computer from 2026. Of course, the specs vary based on the devices and the age of your computer, but all are within the ballpark. Also, we chose to keep the units consistent when comparing the devices, which is why we focus on nanosecond access time rather than the number of clock cycles. Consistency between units, we felt, was more important to get a sense of the magnitudes of difference.

Table of Contents:

00:00 – Why do computers use so many different data memory & storage locations?

02:06 – Why use Registers, Cache, Memory, and Storage?

03:49 – Building the visual representation of data

07:58 – University Lecture on the Memory Hierarchy

08:25 – Cloud Storage

09:09 – How do Solid State Drives Work? Storage

11:52 – How do Hard Disk Drives Work? Storage

13:33 – How does DRAM Work? Memory

15:20 – How does Cache Work?

16:14 – How do Registers Work?

17:40 – Approximate Specifications

18:51 – AI Memory Hierarchy

19:22 – Why does AI need so much Memory and Storage?

22:34 – The AI Memory Hierarchy, Micron Sponsored Segment

26:42 – A Glimpse into the Memory Hierarchy

26:59 – Thank you to our Patrons

This video’s title is still a work in progress- so if you have some ideas let us know!! Here are the options we thought through:

How does Data Work Inside a Computer?

Why Don’t Computers Just Use One Type of Memory? 🖥️💿🛠️

A Complete Explanation of How Data Works Inside Your Computer!!

Why do Computers use 12 (or more) Data Memory & Storage Locations?

What Exactly is the Memory Hierarchy?

Key Branches from this video are:

Animation: Mike Radjabov, Sherdil Davronov, Muazzam Azizova, Max Botirov

Research, Script and Editing: Teddy Tablante

Twitter: @teddytablante

Modeling: Mike Radjabov, Prakash Kakadiya

Voice Over: Phil Lee

Sound Design by Drilu: www.drilu.studio

Sound Design and Mix: Luis Huesca

Erratum:

 Tanenbaum, A. S., & Austin, T. (2013). Structured Computer Organization (6th ed.). Pearson Education.

Wikipedia contributors. “DRAM”. “Hard Drive”. “Memory Hierarchy". “SSD” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, Visited May 24th 2026

Textbooks and Papers

See the DRAM, SSD, and HDD videos for all the references in there.

#DRAM #SSD #Micron