Understanding the figures on Performance graphs
SI Units are shown on graphs and drilldowns when Number Formatting is set to SI Units on System > Administration > Customization > Time and Formats. See Time and Formats
When SI Units is selected graphs and drilldowns will show very small numbers with m (milli) or µ (micro) where appropriate, and large numbers will get k (kilo) or M (mega) assigned.
The k means thousands, and should not be mistaken for kb.
The M means millions, not MB.
Units of measurement
While the units are usually not returned with the data, the metric name often specifies the units, such as % or MB.
Small numbers on a graph
The drilldown graph below is showing some very small numbers:
µ, meaning micro, indicates very small numbers where 47.8µ is actually 0.0000478.
Metric labels and scaling up
For more information see Metric Labels.
When Bytes, Megabytes or Seconds are selected SquaredUp will 'scale up' the label to MB, GB, minutes or hours as appropriate.
The Bar graph below shows a figure of 1675:
In this case, the metric name 'Memory - Available MBytes' tells me that this figure is returned in MB.
When the Metric Label is changed to Megabytes SquaredUp shows 1.64GB:
This is 1675 divided by 1024 and rounded to two decimal places to convert MB into GB.