No need to reinstall Windows after a RAM upgrade.

You’re fine. Windows doesn’t care about RAM size changes. It’ll just see the new memory and start using it.

The only thing to check: make sure your new sticks are running at the right speed and in the correct slots (usually slots 2 and 4 for dual channel). A quick look in BIOS or Task Manager will confirm. If they’re mismatched speeds, the system runs at the slower one—still no reinstall needed.

If you were swapping CPU or motherboard, that’s a different story. But RAM? Plug it in, boot up, move on.