Chances are this is a configuration issue.
For instance, I recently saw a case of this with LMStudio. It turns out that LMStudio doesn't properly handle K/V caching when paired with Claude Code. The solution? Literally the exact same model, but using Ollama as the server application instead. Problem instantly solved.
The other big reason for SSD thrashing is not having enough RAM to handle the model, context, and cache. If you do, then your disk shouldn't be touched at all for model work other than initially loading the model. These things are designed to entirely run from RAM because disk, even the fastest NVMe drives, are slow as shit in comparison. For reference, on my test laptop, it does ~15GB/sec from NVMe, but well over 600GB/sec from RAM. The NVMe speed overall is great for filling content into RAM but once that is done, it is never touched again (save for basic small text/log files)