overlap version
G + C (asynchronous)
G + C (forced synchronous)
Time saved by async
Are the forced sync values too large, pushing the rest of the chart down to tiny tiny sizes?

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Are the green dots mostly close to and aligning to the red dots? This shows asynchronous execution.

Are the green dots mostly higher than the red dots?
No asynchronous shading here, the 2 operations are done practically in serial.