How does Computer Memory Work? π»π
Branch Educationγ»3 minutes read
Millions of operations happen inside a computer when loading programs, with data being copied from SSDs to DRAM for quick access. Micron manufactures DRAM and SSDs, with Crucial offering fast SSDs for smooth gameplay and video editing.
Insights
- DRAM and SSD serve different purposes in a computer system, with DRAM providing fast temporary data storage for quick access to programs and games, while SSDs offer long-term data storage in massive 3D arrays.
- The design of DRAM involves complex structures like banks, rows, and columns, with billions of memory cells organized to efficiently store and access data, utilizing processes like refreshing memory cells and implementing burst buffers to enhance memory operations.
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Recent questions
How do SSDs and DRAM differ?
SSDs store long-term data, while DRAM stores temporarily.
What is the role of DRAM in video games?
DRAM is crucial for quick data access in games.
How are memory cells organized in DRAM?
DRAM memory cells are organized into banks.
What is the function of a 1T1C memory cell in DRAM?
A 1T1C memory cell stores one bit of data.
How does DRAM optimize memory operations?
DRAM optimizes operations through hierarchical row decoding.
Related videos
Summary
00:00
"SSD vs DRAM: Computer Memory Explained"
- Millions of operations occur inside a computer when loading a program or video game, with a common task being copying data from an SSD to DRAM.
- SSDs store data for long-term storage, while DRAM temporarily stores data, with DRAM being significantly faster than SSDs.
- DRAM is limited to a 2D array and temporarily stores one bit per memory cell, while SSDs can store terabytes of data in massive 3D arrays.
- Computers use both SSDs and DRAM, with data being copied from the SSD to DRAM to allow quick access to programs.
- Video games require DRAM for quick access to data, with DRAM capacity being crucial for smooth gameplay.
- DRAM is organized into banks and bank groups, with each chip on a memory channel working in parallel.
- DRAM microchips contain billions of memory cells organized into banks, with each cell storing one bit of data.
- Micron manufactures DRAM and SSDs, with Crucial being a brand under Micron that offers fast SSDs for smooth gameplay and video editing.
- A 1T1C memory cell in DRAM consists of a capacitor and transistor, with the capacitor storing one bit of data and the transistor allowing access to the data.
- Refreshing memory cells is necessary due to electron leakage, with the 1T1C memory cell being one of billions organized into banks in a DRAM die.
15:06
"DRAM Technology: Memory Cell Operation and Optimization"
- Wordlines connect to transistors' control gates in rows, while bitlines connect to the channel opposite each capacitor.
- Activating a wordline connects all capacitors in that row to their corresponding bitlines, activating all memory cells in that row.
- Within a single bank, there are 65,536 rows and 8,192 columns, with a 31-bit address used to activate a group of 8 memory cells.
- A binary number selects a row through a row decoder, activating transistors and connecting capacitors to bitlines.
- The column multiplexer connects specific groups of 8 bitlines to input and output IO wires based on a 10-bit address.
- Reading from memory cells involves sending a read command and address, precharging bitlines, and using sense amplifiers to detect stored values.
- Writing data involves sending a write command, address, and 8 bits, activating rows, and using write drivers to override previous values in capacitors.
- Refreshing memory cells involves closing rows, precharging bitlines, and using sense amplifiers to refill leaked charge, taking 50 nanoseconds per row.
- DRAM handles billions of read and write requests per second while refreshing each bank's memory cells around 16 times a second.
- DDR5 DRAM has 32 banks to increase the likelihood of row hits, reducing access time, and optimizing memory operations.
29:23
Enhanced Memory Chip Design for Efficiency
- A burst buffer, consisting of 128-bit read and write temporary storage locations, is added to the functional diagram, with 128 wires connecting to these buffer locations.
- The 10-bit column address is divided into 6 bits for the multiplexer and 4 bits for the burst buffer, allowing for the temporary loading of 128 values into the burst buffer.
- The burst length is 16, with 8 quickly accessed data locations in the burst buffer connected to read drivers, enabling the rapid reading or writing of 1024 bits per microchip.
- The design includes subdividing the massive array into smaller blocks, using intermediate sense amplifiers, and a hierarchical row decoding scheme to optimize memory cell access and reduce capacitive load, enhancing efficiency and speed.
