4 ms·

Obligatory: What Every Programmer Should Know About Memory From 2007, but still almost entirely relevant. https://lwn.net/Articles/250967/ https://lwn.net/Art

• dragontamer 8y ago
  DDR4 btw has a few major differences: 1. Banks are now split into Bank Groups. Typically 4-bank groups, with 4-banks per group. That's 16-banks total. 2. While waiting for one bank to finish a command (ex: a RAS command), DDR4 RAM allows you to issue commands quickly to other groups, usually in 2-cycles or less. In effect, Bank Group 0 can work in parallel with Group1, Group2, and Group 3. 3. The 4-banks within Bank Group 0 can work in parallel, but at a much slower rate. 4. This allows DDR4 RAM to issue 16-commands in parallel, one to each bank group, as long as certain rules are followed. DDR3 RAM only had 8-banks. This allows DDR4 to be clocked much higher. 5. DDR4 uses less energy than DDR3. ------- That's about it actually. So the vast, vast majority of the information in that document remains relevant today.