I have two Intel 520 Series SSDs in my Mac mini because of speed and silence - but here 6 months after installing it's getting a really slow boot time compared to freshly installed. Earlier it was 18 seconds till login, now it's 48. How could it gain 30 seconds on 6 months? Is there anything wrong? I only use one SSD as the main drive, the other is for recently used files - having backup and external storage for more important things.