I have 2 network adapters on my Windows 10 machine - one of it is an integrated wifi chip on the motherboard, the other is a PCI express network card I bought some time ago.

The integrated network chip can only receive 2.4ghz while the standalone network card can receive both 2.4ghz and 5ghz.

Right now, both the cards are connected to my home wifi connection. The integrated chip to the 2.4ghz wifi while the standalone card to the 5ghz wifi.

In a situation like this, how does my computer decide which network card to use?

Will my computer be end up using the 2.4ghz or 5ghz wifi connection?

Or will both cards function together and boost the speed?

Or will the 2 cards act as redundancy for each other in an event when one got disconnected my computer is still online because the other card is still connected?


Or will both cards function together and boost the speed?

let me start by answering this part: No.

In almost all cases have two or more network connections to the same network does not boost speed. In the cases of two wired 100Mbit NIC connections you would still get only 100Mbit.

There are exceptions to this, but then you need to take special care to bind these interfaces into one. That requires special software (search on terms like bounding, lagg etc). And often that does not double the speed of a single connection, though it will help if you are dozens of connections.

That must for wired. Now you have wireless. That means both cards can try to use the same frequency, effectively jamming each other. Different wireless channels can help here, but sine you probably only have one access point this is probably useless.

OK, so much for a generic no. Now in to windows and its default actions with no special care.

TCP/IP networking uses the interface with the lowest metric. That metric can represent anything. E.g. cost per use. In windows it the default metric however is set based on the speed of the connection. Since the 5GHz card is probably the fastest this is the connection which will be used, and this connection alone.

Which means that the generic default answer is a 'no', but in special cases it can be turned into a 'yes'. For practical considerations just disable the 2.4GHz only device and see if that saves some power and only use the 5+2.4 GHz card.

  • If I have one of the network adapters disabled in the Windows control panel, would it stop all of that frequency jamming issue? – xenon Oct 1 '17 at 23:24
  • Yes. The card should not be active and not transmit anything. Depending on how drivers are written it might also consume less power. (Which in a desktop is not a big issue, but ...) – Hennes Oct 2 '17 at 14:52

Technical details aside, you are asking for trouble in this situation. It will not boost speed and is likely to cause unintended consequences. The reasons for which I'm not going to get in to because it is out of scope.

However, technically Windows will automatically set metric values for each connection based on link speed. The metric value tells Windows which route/adapter to use when there are multiple paths to the same destination. A higher metric value, indicates a higher cost, and thus a lower priority.

Your 5Ghz connection is likely a higher link speed and will be preferred over the 2.4Ghz connection. The worst case scenario is that both connections are equal in speed but one is far less reliable, as is often the case with 2.4Ghz. Being 5Ghz is a cleaner band and a more stable connection, there would be no reason to keep your 2.4Ghz connection active.

More info about Windows automatic metric: https://support.microsoft.com/en-us/help/299540/an-explanation-of-the-automatic-metric-feature-for-ipv4-routes

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