R6400 v1 Speed Issue

Hi slyda007 

Troubleshooting AC speeds can be tricky.  You've done some of the right things already.  I can help you with a few others.

First of all, remember a few things:

• First, expectations: over-the-air bitrate is not the same as throughput bitrate.  An AC1750 router like yours is capable of 1300kbps on 5GHz AC and 450kbps over the 2.4GHz n, but not simultaneously.  So 1300kbps is the highest over the air rate bitrate for any one device.  And the bitrate in this sense means that when it is actually transmitting data, that is the number of bits that can travel per second.  Wi-fi's protocol overhead eats up a lot of that, Preamble, guard spacing, interframe spacing, back-off periods, acknowledgements - all those slow down wireless a lot more than wired.
• Your laptop's chipset sounds like it may be the best of the bunch.  The other devices in a multi-device environment may slow things down considerably for all involved.  I can't tell from what you're posting on the Intel one (I need the model number), but a lot of Intel ones that come built-in to PCs are pretty limited.
• Even when you do have several devices with individually good chipsets, not all of them play well with others.  Many chipsets and/or the way they are implemented or their drivers are written are done such that they exploit wi-fi protocols to make themselves faster at the expense of other devices.  This is so that they can publish great stats for how well they perform in the "real world" when for their stats "real world" means their device connected on a wi-fi network all alone.  All it takes is two of these on the network at once and the throughput of each drops by more than half.
• The best speeds are on 5Ghz channels in AC, and those frequencies are attenuated even more than 2.4GHz by almost everything.  At that frequency, even the humidity in the air attenuates the signal.

Some advice:

• Test each device alone on the network, one at a time, at various ranges from the base station.  Try, if you can, to see the actual link rate you are connected at and what that link rate is doing at various ranges.
• Once you do the above, try and get a sense for how each device interoperates with each other device.  Try device pairs on the network at a time, trying the different combinations.  This can quickly spiral to a lot of testing, but it's useful to do for the main players (laptop + PC, for example)
• QoS isn't the only setting that affects how multiple devices work with each other.  There is also the Airtime Fairness settings, which attempts to give each device an equal time slot rather than letting each one operate at the speed it is requesting.  This is a setting that Netgear put in due to my third point above.  See page 122 of your device's manual on how to change this setting.  You can also try with and without beamforming.
• Not all the settings on your router will interface with all your devices well.  For example, not all your devices will themselves support beamforming.  I would suggest reserving the 5GHz one for only those devices that support 1300kbps rates, beamforming, and that work well with others.  Then relegate those devices without high speed AC support or those that don't work well with others to the 2.4GHz N network.
• I'm not sure if the original R6400 supports other advanced wi-fi parameters, like short preamble, since the manual I'm looking at doesn't mention them.  I think your model does support those settings.  Some of those can affect how well single and multiple devices perform on the network and may be useful to play with.  Keep in mind, with some of them it is easy to make the network work better for one or even two but worse for other devices.
• Get as many devices off the wireless networks as you can, especially fixed assets like PCs.  Good ole wired will always be better in and of itself and will relieve air congestion.

Remember, wi-fi ALWAYS is a trade of performance for convenience, no matter what the marketing guys say.