Transaction Groups taking 10+ seconds to execute

Recently upgraded from 8.0.2 platform to 8.1.1 across multiple gateways (Main and Testing environments). Started noticing that the Main environment was showing some gaps in trends from the db.
Further investigation showed that transaction groups were taking upwards of 10-12 seconds to complete where prior executions were <1s in 8.0.2.
Utilizing a sort of buffering between transaction groups and PLC where 500 rows are populated and the block transactions get it to the db (essentially giving transaction 5s to complete before next buffer is filled and requires to be dumped).
However, Testing environment is not showing the behavior like Main environment.
High level differences between environments is Main system is redundant and Testing system has more resources (CPU and Memory) due to more equipment residing currently in the testing system.
Did disable Redundancy on Main system to see if that helped, but did not seem to make a difference.
Looking for any thoughts/feedback or if anyone has noticed a similar problem with transaction groups in 8.1.1.