In this case we do 200M ops (random write and read) with 6GB of Buffer pool. It wrote ~73GB of data including log files. The aim of graph is to show the variability in the reads and writes. The data for write is shown with both log ON and OFF. Please note that wih log ON the variation is write is more, this is because we frequently flush log file to disk apart from the page in/out for index and data pages. In case of log OFF this there is no write for log. In case of read there is no log activity.