Appears that whatever is using your disk might now have enough CPU attention to get its job done without blocking disk accesses. Make sure you have no disk utilities that are supposed to improve your disk throughput.
For example, the Samsung RAPID technology improves average SSD transfer rates significantly, but it does that at the expense of latencies up to 30ms, which would create hiccups (disk spikes) on all DAWs.
DAWs rely upon having the smallest maximum latency possible (I call it ‘best worst case’). Turn off all stuff that is designed for optimising non-real-time scenarios.
An SSD for the OS/progams drive will not give any performance benefits, other than speed up startup and program load times, unless the cause of your issue is some driver/service activity that is interfering with disk operations.
Make sure all unnecessary motherboard utilities/services are uninstalled, as they are typically designed to make their products look good, rather than your program performance.
a) SSDs will take storage off the critical path for DAW performance. If you still have problems, it is NOT the technology per se, but elsewhere, like drivers, firmware, services (non-OS), plugins and software.
b) Don’t be impressed by tests that indicate fantastic transfer rates, because they can only get those figures by keeping the channels saturated, thereby forcing ALL data to experience the maximum latencies/delays. A channel needs to run at well below its maximum capacity to guarantee low latencies, as it allows incidental OS and program ops without impact.