Based on the details of this situation, it's likely you may be experiencing compatibility issues. It may be that your system is not fully compatible with the Intel® Wireless adapters mentioned and this may be causing the inconvenience with speeds.
We would like to take this opportunity and inform you that Intel does not support integration which is when the original wireless adapter is replaced by a different one. Please, check this link for further information on this matter: Regulatory Information Regarding Hardware Installation or Upgrade
We recommend to contact Dell* and check with them if they offer support for these adapters on this specific system you have. For your convenience, through this link you may find Dell's contact information: Computer Manufacturer Support Websites
On our best effort to assist you, here are some tips that might help minimize or resolve the issue with speed considering you have mentioned you are using the latest drivers for our adapters according to your description, but just to guarantee you have our latest drivers here are the links to them so you can double check:
Downloads for Intel® Dual Band Wireless-AC 8260
Downloads for Intel® Dual Band Wireless-AC 7265
*Please, make sure to install the version according to your OS version and architecture 32 or 64 Bit
On our best effort to assist you, considering this is an integration, here are a few tips that help you improve and/or resolve this situation.
1. Make sure all files from the previous adapter has been removed completely.
2. Then, proceed to a clean installation of the drivers. This is how you can do it: 3. Go to Control Panel, Programs and Features and Uninstall "Intel® PROSet/Wireless Software", if it is installed. When prompted, choose the option to "Discard settings".
3. In Control Panel, Device Manager, Network Adapters, right click on the Intel® Dual Band Wireless-AC 7265 or Intel® Dual Band Wireless-AC 8260 and uninstall it. Make sure you mark the option to "Delete the driver software for this device".
4. Reboot the PC or scan for hardware changes, check device manager and if an older driver is detected and installed, repeat the actions to uninstall and delete it as well. Repeat this process until the OS does not allow deleting the driver, or until the controller shows as Unknown Device.
5. Install the Intel® Wireless driver. During the first steps of PROSet/Wireless installation, make sure to customize the installation and install all the 3 driver components.
Additionally to that, these are other alternatives:
Use WPA2 security - For the high speeds on wireless N or AC routers you must use WPA2 security with AES encryption. Using WPA or WEP security with TKIP encryption will dramatically reduce bandwidth. Most routers offer a mixed WPA/WPA2 mode, but you should use WPA2 only.
Change your wireless channel - Changing your wireless channel might help increase range and performance, especially if you have neighboring networks set on the same channel or interference from other electronics. It’s best to check channel usage with a program like Vistumbler or inSSIDer, but you can simply try other channels as well to see which one is best.
For 2.4GHz routers (the most common), channel 6 is the default for most routers, so stay away from it. Try channel 1 or 11, the other two other non-overlapping channels. For 5GHz wireless N or AC routers, you shouldn’t have much of an interference issue since it’s less commonly used. But you might try changing to another channel as well.
*NOTE: These third-party links are being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.
Change default channel width of router - The higher speeds of wireless N and AC can only be achieved by using the 40MHz wide channels. For wireless N (and possibly wireless AC), the default channel-width set on routers is only 20MHz. But you can login to the control panel of the router and in the wireless settings change the channel-width to auto 20/40MHz.
Upgrade your router - your router plays a very important role on the performance and speeds. Please, consider looking into the router configuration such as 802.11n or 802.11ac. configuration. Check if your router has MU-MIMO as it helps increase range and speed on the 5GHz frequency band that’s less congested. Contacting the manufacturer for additional support is important.
We hope this helps you to resolve this situation.
Thanks. Did all of that, no change. Dell won't help either so i think I'll just toss this chip into the drawer with the 7265 and revert back to the Broadcom. I appreciate the response given but I question the non-support policy - why are these are sold on retail locations like Amazon for people to buy and use if the vendor does not support integration when they used?
Unfortunately there is no way to have control over what a re-seller can or can not do. One thing we can guarantee is that we do not sell our Wireless Adapters to end-user, only to OEMs ( Original Equipment Manufacturer) so they can do all the necessary adjustments and modifications in order to be fully compatible with the type of system they plan to integrate and when they do that, they may even provide their own customized drivers.
Please let us know if you have any further questions or doubts.
Thank you for your cooperation and going the extra mile and letting other potential buyer to know about that. Is there any thing else we can do to assist you? Should you have any further questions or doubts, please, do not hesitate to contact us.