SSDs (many of them at least) actually do make little noises when they're busy! I noticed my PC was making a noise, and I went on a wild goose chase trying to track it down. (Was something wrong with one of the fans? Was it coil whine from the GPU?) I didn't immediately suspect the SSD, because everyone claims they're silent. Then I finally realized the noise corresponded with disk activity, and I found a YouTube video confirming it: https://www.youtube.com/watch?v=KS-BHI667po