I ran the dashboard throughput test from three different AP models I have (MR55, MR56 and CW9166) and got 81-82 Mbps from all three. Testing from the MX75 gives 486Mbps and as it is a 500Mbps line that one seems good.
As you can see, the APs processing power limits their performance testing capabilities, though not the actual performance for clients.
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