Our overflow-130k Btree Throughput performance charts show significant volatility from run to run, in some cases the stats change from 400,000 to 2,100,000 and then back across three consecutive commits.

This ticket is to investigate the overflow-130k test configuration, and if possible apply a fix to reduce volatility. Ideally we get volatility to less than 10% but any improvements are good. 
For this purpose the ticket is time-boxed to 5 story points.