Slow/Unstable Internet Speeds after Win 10 Update

[Zander490]

My internet on my custom desktop, as far as I can remember, has functioned fine for a long time now. However, after upgrading to windows 10 and having it around for a while, I noticed a sharp decrease in internet speed. I've tried multiple solutions, but nothing seems to have worked. It only seemed to start occurring after installing Windows 10, but the slowdown Is also present in Windows 7.

-My specs-:
Service: Cable
Provider: AT&T
Connection: Wifi
Router/Modem: Arris NVG589
Number of Devices: 19? (11 on)
Adapter: Intel® Dual Band Wireless-AC 7260 + Bluetooth* for Desktop
Driver Version: 17.16.0.4
Driver Date: 3/23/2015
Model: Custom ( http://pcpartpicker.com/user/Zander490/saved/gw4MnQ )
OS: Windows 10/Windows 7 (current)
SpeedTest: 1.80 Mbps


Attempted Fixes (X = No effect, 0 = Some effect, ? = Unknown effect)
X Automatic Troubleshooter
X Driver update ( https://downloadcenter.intel.com/download/25172/Intel-PROSet-Wireless-Software-for-Bluetooth-Technology-for-Windows-10-64-bit-WP- )
X Virus Scan
X Removing excess browser extensions (Chrome)
X Clearing Cache (Chrome)
0 Booting to Ubuntu? (Faster speeds after idling for a while)
? Switching to Microsoft Edge (12 Mbps on 8/8, 2.41 Mbps on 8/9)
X Booting into Safe Mode with Networking (No Wifi option)
X Disabling Internet sharing option
X Disabled Power Saving option on Wifi adapter
X Switching to FireFox (2.12 Mbps)
X Turned off sending updates to other computers
X Turned off nearby A/V Receiver with bluetooth and radio
X Rolled back wifi adapter driver
X Updated Wifi Adapter via Windows Update
X Reset Network Settings ("ipconfig / release, ipconfig /renew")
X Uninstalling (and Deleting) Wifi Driver
X Reverting to windows 7

Notes
Laptop with similar (if not the same) adapter connects normally (Acer Aspire V 15)
Started after Updating to windows 10 (May not have noticed until now)
Worked fine on windows 7 (until reverting)
Wireless Network Connection Status > General > Connection > Speed: 144 Mbps ~ 52 Mbps
Analyzed hard disk for needed Defragmentation, 0% fragmented
Using http://www.speedtest.net/ for testing

 

[Zander490]

I fixed it! Turns out it wasn't the operating system at all. Apparently I had mistakenly installed a program called "cFosSpeed Internet Accelerator + Ping Optimizer" during my transition to Windows 10, thinking it was an essential driver. I disabled it by going to Control Panel > Network and Internet > Network Connections > Wireless Network Connection Properties > Networking and deselecting "cFosSpeed for faster internet connections (NDIS 6)". This instantly improved my download and upload speeds. I've uninstalled it now, and XfastLan is bringing up an error, but the internet speed is still improved.

 

[lynspottery]

Well glad you found a fix for yours...but I do not have it installed and I still experience the slow internet speed. So is there something else that might be causing this?