I recently purchased a Inspiron 15 3567. I am just now realizing that the wifi card only picks up 2.5Ghz (Qualcomm QCA9565 802.11b/g/n). I have a AC router and would like to enjoy the speed it provides. Any suggestions on a dual band wireless card? Any help is appreciated.
If your system uses Mini-PCIe (aka Half Mini Card), I personally think the best dual band WiFi card that was released in that form factor is the Intel 7260HMW. Make sure you do NOT get the 7260NGW, which is the same card in the newer M.2/NGFF form factor and therefore won't fit in a Mini-PCIe slot. If your system does in fact use an M.2/NGFF slot for the WiFi card, I would go with the newer Intel 8265. Or you may wish to wait for the announced but not yet released Intel 9260, which is an 802.11ac Wave 2 product and therefore capable of significantly higher speeds if your router supports those features (like MU-MIMO). But even if your current router doesn't, waiting a bit wouldn't be a bad idea for simple futureproofing. Do NOT get the related Intel 9560 module, since that requires a newer CPU that has some tech normally found on the WiFi card built into the CPU itself.
WAIT A SECOND! I should've mentioned that you should check the number of antennas available in your system. All of the cards I mentioned are dual antenna cards, and dual antenna cards don't work properly if only a single antenna is connected to them; you'd want a card designed to operate on a single antenna. I can't any details about your current WiFi card, but even if it's a single-antenna card, it's still possible that the system design includes a second antenna that in your particular case would currently be disconnected, in which case you'd just connect it to your replacement card along with the primary antenna. But if you find that your system only has a single antenna at all, you'd want to find a single antenna replacement. I don't have any immediate recommendations on that front.