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I want to replace a preinstalled Qualcomm Atheros WiFi/Bluetooth M.2 2230 card on my motherboard (ASUS Maximus VIII Impact) with another that has better driver support. This is what the card I want to replace looks like.

enter image description here

As you can see, its edge connector has all of its contacts. I want to swap this card with an Intel 8265 M.2 2230 card that looks like this.

enter image description here

But this card seems to be missing contacts. Here's another card from Intel with model number 7260 that is missing the same contacts on the edge connector.

enter image description here

Both of these cards have fewer contacts. Why do these cards have fewer contacts than the preinstalled card and will this cause problems when I swap the old one out for the new one?

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    \$\begingroup\$ Just to let yo know, I have replaced the stock Qualcomm card in the M8I with an Intel AC 9260 card. Works perfect, no compatibility / whitelist issues whatsoever. Hardware wise the Qualcomm card is fine its just the drivers that let it down (although to be fair they have been improved now to the point where the card is perfectly usable - at launch they were a nightmare). Intel is where its at with regard to AC cards, and since you can get the AC 9260 for c.a. 30 USD on Ali it makes perfect sense to ditch the stock card. \$\endgroup\$ – MtothaJ May 10 '18 at 21:46
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The contacts are missing because they're not used. The A-key variant of the m.2 spec has provisions for display port signals while the E-key variant drops the display port and adds SDIO, UART and PCM (aka I2S), I'd bet those are the ones missing, especially as this is a dual use card (as it has both the A and E key slots present, any pins that differ between the two slots have to be removed). It's probably not using the USB or the second PCIe lane either.

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  • \$\begingroup\$ That makes sense, but could you explain why the Qualcomm Atheros PCB has these extra contacts? \$\endgroup\$ – Wandering Fool Sep 24 '16 at 22:02
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    \$\begingroup\$ Not every manufacturer bothers to remove the extra pads (I wouldn't), even if they're unconnected. I'll bet if you look closely at the extra pads you'll see they don't have any traces or vias going to them \$\endgroup\$ – Sam Sep 24 '16 at 22:16
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    \$\begingroup\$ Looking at the first photo, the contacts that are missing in the others, appear to be "islands" with no track disappearing into the board and no via. Check carefully on the actual board and I think you'll find that's the case. In which case, the other boards are compatible (at least at the connector level). Somebody at Intel has probably spent way too much time integrating the area of all those pads * 2 microns to calculate the volume of gold thereby saved, and now they have to delete the pads until the cost of his calculation has been paid off. \$\endgroup\$ – Brian Drummond Sep 24 '16 at 22:24
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    \$\begingroup\$ I can see that there are no traces or vias on the original PCB picture where there should be missing contacts. You are absolutely right! \$\endgroup\$ – Wandering Fool Sep 24 '16 at 23:12
  • \$\begingroup\$ Please be careful with your substitution. The M.2 is a muti-function socket (USB2, USB3, HSIC, SSIC, PCIe, HDMI, I2C, UART, and several sideband signals) where a manufacturer can elect to use only a subset of functions. If several functions are connected, firmware has options to configure, but... The ASUS description is not overly open about what is routed to this slot for the Qualcomm modem. Intel's card can have a different set of interfaces to operate, and ASUS BIOS might be unable to configure it properly. \$\endgroup\$ – Ale..chenski Sep 25 '16 at 2:10

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