> RAM sticks have a little tag chip that tells a PC "how much RAM this stick has", but RAM chips themselves don't - so the device has to infer its RAM capacity from elsewhere
replyI'm surprised that in 2026 this is still true.
You could easily fit a little microcontroller on the die of each RAM chip which reports its make/model/manufacturing date, capacity and capabilities, can be triggered to run self-tests, etc. If they aren't doing that yet, I'm surprised that they aren't.
Why bother with the expense if you are permanently soldering it in anyway?
replyWell, it turns out they actually are bothering – while in DDR thru DDR4, the mode registers are write-only, LPDDR2 onwards have an MRR (Mode Register Read) command, which the CPU/chipset can use to inspect the manufacturer and capacity; and DDR5 has copied the same facility from LPDDR.
replyUpgrading my RAM firmware when
reply