Networking problem Aspire e5-571

Hi. I have an Aspire e5-571, which has a Broadcom 802.11n network adapter. It has an infuriating habit of suddenly going into very low download speed (3 or 4 Mbps) after running at 40ish Mbps. Often the upload speed is OK. The only way to restore the speed is to reset the adapter. We have tablets, phones and another PC that work consistently at high speeds so I have ruled out the router (it happens on 2 different routers anyway). I have updated the adapter to the latest drivers, changed various settings in the adapter, moved the PC closer to the router, all to no avail. Does anybody have any idea what is going on here? Any logs I can check for more information?

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philetus

If all your other devices are working fine, the problem has to be the adapter or the driver. Has this happened from the first time you started using this laptop?

gerryf

Thanks for your reply. Not from new. I think it's a recent thing, maybe started happening a few months ago. Initially I thought interference from neighbouring houses but another pc in the same room never fails. And it happens on all channels. Gerry.

philetus

Could be you have a virus. If you don't have it, download Malwarebytes free and Rougekiller free and run them.
https://www.malwarebytes.com/ https://www.adlice.com/download/roguekiller/
They are safe and you can always uninstall them after.