Slow WiFi with External Display

[lehman310]

I am having a strange issue with my Mid 2012 Macbook Air. Whenever I connect my external display via Thunderbolt to DVI adapter, my WiFi speed goes from 45mbps to <0.5mbps. The same issue does not occur when I use Thunderbolt to HDMI to connect to TV. In addition to this, I get around 70mbps from the same location on my iPad (right next to router on 100mbps connection) so I am wondering if my WiFi card is going bad or if theres something I can do on the software end of things.

Thanks!


Edit: Ive changed the external display resolution and I can get 25mbps but its still not what I get without display connected.

 

[alphaod]

Sounds like the adapter you're using isn't shielded correctly and perhaps causing interference? I have an adapter that I bought that did this. I would cause my WiFi, Bluetooth, and Logitech receiver RF to all drop.

Unplugging it immediately resolved the issue.

 

[Boyd01]

I use a DVI adapter with an old 23" Cinema display on my 2013 MBA every day. It has no effect on wifi - I get about 60MB/s copying files on the LAN with 802.11ac.

I would try another adapter and another display and see what happens.