@Mardler
I think that'll be due to the arrangement of 40MHz of bandwidth in the 2.4 GHz band, and whether what the manual refers to as the "sideband" (second 20MHz portion) is above or below the main 20Mhz channel.
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The s3 has a 80mhz band capable reciever. It forces itself to 40mhz only mode on 2.4ghz even if the router is configured to allow 80.
Yes I know it's a very old post, but it's full of things that are horribly wrong. I'm pretty sure 2.4GHz only has 11n which only has 20 or 40 MHz channel widths.
Also most of these devices listed are 40mhz wide max so 72mbps max on N.
It's not just the bandwidth, it's the number of spatial streams. 11n is:
1 stream, 20MHz is 65, or 72 Mbps with SGI (Short Guard Interval).
1 stream, 40MHz is 135, or 150 Mbps with SGI.