16GB is doable on most 7-year-old PCs.

Probably, yes. A seven-year-old PC (say ~2017) almost certainly shipped with a motherboard that supports 16GB — often 32GB. The real limit is usually the CPU and the number of slots, not some hard 8GB cap.

The key question: do you have two RAM slots open? If your current 8GB is a single stick, you can just add another 8GB stick of the same speed and voltage. If it’s two 4GB sticks, you’ll need to replace both with two 8GB sticks. Either way, DDR4 or DDR3 — check what your board uses (CPUID or just look at the sticks). Most consumer boards from that era handle 16GB without issue.

Don’t overthink it. If your motherboard manual or a quick scan with CPU-Z shows support for 16