I understand you are having problems with the Intel® Rapid Storage Technology but let me help you.
It is very strange that this is happening after the memory upgrade but there are some steps I want you to try:
- Update the BIOS.
- Install the latest Management Engine provided by your Computer Manufacture.
- Test the system with the same memory than before (4GB).
Adding more memory In the system should not affect the system in anything else but performance.
Besides the steps above, you can try disabling the notifications under the Intel® Rapid Storage Technology > Preferences Tab.