Hello Mediane,
Remember that RAID 5 array will verify and repair any errors on the raid structure, therefore a slow performance will be an expected behavior. However, could you please access the Ctrl+I menu and let me know check the Raid Status?
Also, please copy-paste or attach the report generated within the Intel® Rapid Storage Technology:
- Open the Intel Rapid Storage Technology user interface (Start » Programs » Intel » Intel® Rapid Storage Technology).
- Click the Help icon.
- Click the System Report icon.
Let me know the model number of your system?
Regards,