Read the markings on the chips.

Yes, you can find the exact JEDEC spec without a schematic. The chips themselves tell you everything.

Pop the bottom panel off your laptop. Find the small black rectangles that are the RAM chips. They’ll have a part number printed on them, something like MT52L1G32D4PG-093 or H9HCNNN8KUMLHR-NME. That string is your answer.

Google that part number, and you’ll get the datasheet from the manufacturer (Micron, Samsung, SK Hynix, etc.) which lists timings, voltage, density, and JEDEC compliance. It’s the same document the board designer used.

If you can’t open the laptop (e.g. it’s glued shut), try HWiNFO64 or CPU-Z. They can read SPD data from the RAM, which includes JEDEC timings and voltage. But those tools only work if the RAM is visible to the OS. Some soldered RAM is locked down. In that case, physical inspection is your only reliable route.

The chip’s part number is the key. Write it down, search it, and you’re done.