AC-7265 Frequent disconnects/Painfully slow when connected

Hello all,

I've had my new laptop for about 2 months now, and there has been a wifi problem since day 1. My laptop is running Windows 8.1 with Intel DualBand Wireless AC7265.

Here are the list of problems that I've encountered.

1. I would have 5 bars showing on the taskbar, but the internet is painfully slow.
2. It also just drops connection if I open 2 or more tabs with images in them, as if it can't take it and just decides to stop trying. None of my other computers, including a mid-2009 macbook pro, is having this kind of problem as they run completely fine, fast and reliable.

I don't have these problems at my apartment, with the following conditions:

1. The router is basically 15 feet away from the laptop with no walls between the laptop and the router.
2. Comcast modem that doubles as a wireless router.

I have problems in my actual house, where:

1. The router is further away with walls between the laptop and the router. However, moving my laptop to 5 ft away from the router with no occlusion did not fix anything.
2. Comcast modem that requires a separate wireless router (Belkin AC1200 Dual Band AC+).

Any advice is greatly appreciated. Thanks.