iP5s bcome slightly slow, then ip5 gg la

i'm not sure if anyone is facing this problem but at least for me my line of iOS 8.1 devices are suffering from WiFi slowdown.

My MacBook works just fine when connected, my Android devices works flawlessly, my dad's iPad mini 1 which is still on iOS7 works wonderfully as well.
After updating to iOS8 on my iPad mini 2 and iPhone 5s, I've been noticing a lot of freezing and slowdowns on both my devices. Instagram refuses to load, tweets doesn't send and WhatsApp texts takes ages to send (the texts are just a few bits in size, c'mon) 

One thing is Safari on 8.1, it freezes or just stops loading halfway and refuses to load. It's painstakingly slow. I cannot bare with it and changed it to chrome although I always prefer Safari. I've been on Apple forums and this seems to be a widely reported issue.

I initially thought that this was my Unifi's issue (I'm on 10Mbps) but when I switched to my Android device (OnePlus and M8), everything works fine and flawlessly. So I suspect iOS8 is definitely the culprit.

I've tried resetting network settings and other 'fixes' doesn't work for me. All I can hope is Apple is working on a fix and release an update ASAP.
Anyone facing the same problem here? 

My whatsapp keep crashing recently. Anyone experience the same issue?