16GB is worth it for a 6-year-old gaming PC

Yes, the price-to-performance ratio is excellent.

An 8GB to 16GB jump is one of the cheapest upgrades you can do short of swapping in an SSD. For a six-year-old PC, you’re probably looking at DDR3 or early DDR4 – used sticks go for $20-30. And the difference in modern games is night and day: 8GB causes constant stuttering as the system swaps to disk.

There’s a catch: if your CPU is a low-end model (i3 or FX-4xxx) or your GPU is a GTX 960