really doesn't matter what OS you have.
If your WiFi connection is a potato, it won't matter how great your device specs are.

Although, if you have a good WiFi connection, but your device's WiFi card isn't too great
current devices tend to have wifi cards with support for 802.11n and/or 802.11ac
Attachment 151184

VPNs (especially the free ones) will likely slow down your connection
(since your traffic would have to first go to the VPN, then to wherever the AL servers are located)