I bought this VN7 591G 70RT and had absolutely no wifi problems
I installed a SSD drive to boot the OS (win 8.1) from there, but got the OS messed up, so a friend helped me and installed a clean copy of the OS, deleted the OS from the HDD.
Donwloaded and installed all the drivers and BOOM... wifi sucks! very slow, poor signal, disconnects...
This laptop was manufactured on march 2015, I guess by that date they did fix the wifi issues, but drivers may not be updated in the website?
driver date: 21/8/2014

also there is no AC wireless mode as you can see in the list. This laptop comes with 802.11ac
Is there a relation between these?
HELP!