So basically, I had Intel Centrino Advanced N-6235 which worked like absolute garbage, had the same problems like what this card has now. So I bought Intel Dual Band AC7260, which was a bitch to install and it took over 2-3hours opening my laptop case, because it was super hard (hidden screws everywhere!). So first few weeks it was working pretty well, even though it dropped wifi connection couple of times, my internet latency was consistent and always good (ping in games was constant). However, after that period, I have no idea what happened but since last week, the connection has been very very shit. Constant lag spikes in games, every 3-4sec. Tried every game (so it's not the server's fault). Also I can feel it when playing videos, sometimes videos just randomly stop to buffer, or webpages suddenly load slowly. So basically I changed the card for nothing. Tried every setting suggested on the forum, no results. Updated driver to the latest version (for windows 8.1). Updated Bios. Still shit internet. Had the Centrino card for 2 years which was dropping like crazy (which forced me to use cable). But now I can't use wired connections, so I am forced to use wifi. Depressingly now I use iphone internet which I connect through usb (to avoid shitty card) that works better than all the Intel cards.
So, my only theory is that some windows update caused problems with the card (I've read many posts that say the card has problems with windows 8.1). Other then that, I have no idea why it would start working badly. I didn't touch anything when it was working good (It was still dropping wifi, but didnt have ping spikes). The other card, Centrino 6235 was working shitty since the purchase of the laptop, it did exactly what the 7260 card is doing now. I've looked at posts about it in the past, and I've found that Intel had many faulty 6235 cards which is why I replaced it with 7260. VERY VERY FRUSTRATING.
I have windows 8.1
Laptop: Samsung series 7 gamer
My router is technicolor
Thanks man, that fixed the issue. Basically whoever has the same problem, follow Vigz' solution in the above link (just need to disable ScanWhenAssociated). Also whoever is looking to get a wireless network card for a laptop, stay away, Intel network cards are very very bad.