WiFi adapter problem

So I have an optic fibre at home and it gave me no problems on my old computer, running Windows 7. I recently got a new one, now it's running Windows 8.1 and also here are the complete stats:

OS Version: Microsoft Windows 8.1, 64 bit
Processor: AMD FX(tm)-8320 Eight-Core Processor, AMD64 Family 21 Model 2 Stepping 0
Processor Count: 8
RAM: 8149 Mb
Graphics Card: NVIDIA GeForce GTX 760, -2048 Mb
Hard Drives: C: Total - 511648 MB, Free - 415484 MB; D: Total - 1395727 MB, Free - 696634 MB;
Motherboard: ASRock, 990FX Extreme3
Antivirus: McAfee Anti-Virus and Anti-Spyware, Updated and Enabled

The problem I have is that when I start using the internet on wireless heavily (like say, downloading at a speed of 4 megabytes per second), the computer loses connection with the WiFi adapter - I have a TP - Link TL-WN823N adapter which according to Microsoft compatibility checker is supposed to work OK with Windows 8.1, though I know that those compatibility checks aren't always very good. What happens is that - say - when I am downloading a game, it would periodically disconnect when it's downloading at a high speed and then reconnect automatically, although some times I would have to plug it and unplug it. Any ideas why would this happen? A while ago I had some problems with USB devices in general - like all of them would some times lose connection, but then I changed my old adapter to this one (the old one kept disconnecting too) and now it only happens with the adapter, and while downloading stuff at high speed, which is not too bad when it's Steam because you can limit download speeds, but with things like UPlay, sadly you can't. So any ideas what may be causing this?

 

I did. I also unchecked the bit in the device manager which allows the system to put the device to sleep.