One of your RAM chips isn't soldered right.

Yes, you’re looking at a detection failure, and it’s almost certainly because one chip has a cold or broken solder joint.

When a laptop boots but only sees half the installed memory, it means both chips aren’t talking to the CPU. Soldered RAM is finicky – one slightly missed pad or a joint that didn’t fully melt will kill that channel. The machine doesn’t throw an error because it can still run on the working chip.

Your best bet: reflow the connections on the non-working chip. If you have a hot air station, give it a careful reheat with flux. If you’re using a soldering iron, check for bridged or lifted pads. A multimeter in continuity mode can confirm which pins are dead.

Don’t assume it’s a dead chip yet – bad solder is way more common than a fried BGA.

Future-you will thank you for fixing it now instead of letting it haunt you later.