You can try the "patched" version of the Graph Explorer (2.0.3). Download the file below:This is a bug in the perfgraph's template when it builds the graph... the new units of measurement CAN NOT start with a # so 5_minute_avg or whatever starts with a 5 and breaks the Highcharts graphs.
Don't unizip it. Install it as you would any other component:
Admin->Manage Components->Browse->graphexplorer.zip->Upload Component
Let me know if this fixed your graphs for the CPU Usage.