The Cache Memory options is what it caches when you are using Power BI in the Query Editor. So it caches the data to a point (normally first 100 rows) so that it does not have to pull down all the data when still in the Query Editor.
So if you are looking to increase the speed at which it imports the data, I would say that currently it is pretty quick with 10 million rows/min.
If you are looking to make it faster, the only things that come to mind is to ensure that your connectivity is as fast as possible. Also the more "Applied Steps" you have in your tables in the Query Editor can also slow down the import process. As well as ensure (which it appears it is doing) to ensure that the View is as optimal as possible from your SQL View.
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