eDirectory cache performance reduced after upgrading to 8.7.3 ir9

Customer upgraded from 8.7.3.1 to 8.7.3.9, immediately noticed a drop in cache performance within database cache screens in iMonitor. Also noticed the IDM Active directory driver performance was severely affected - lookup of associations was reduced from 6 seconds to 40+ seconds.

Increased allocated database cache to 1.5gb and block cache percentage to 25%

It should be noted that in most cases 1gb is sufficient as per KB 3178089 - eDirectory best practices guide, however this is only a rule of thumb and care should be taken to baseline your directory performance and tune as necessary according to the information provided within iMonitor.