I'm at a complete loss here. *Solved*

[Ellis_D]

So for the last few days, I've been having a myriad of issues with my desktop Wifi. I first noticed it while playing Overwatch when my ping was inordinately high (I'm usually getting about 20-30ms ping but I'm now seeing about 150ms) I was normally getting and so much rubberbanding that it was pretty much unplayable. It also seemed like web pages were loading slower. Not so much that the content was loading slower but it was taking longer just to contact the web pages though running a Speed Test would result in nominal ping and download/upload speeds but for whatever reason, everything I'm doing involving a network connection seems sluggish. Maybe Packet loss?. So some background information....

I was digging into the internals of my PC and decided to change the PCIe slot my wifi card was using so its ugly green PCB was less visable. I moved it from the first 1x slot to the third (right under my Video Card) and this is when I first started. That card was an old TP-Link Wireless N card and I'm connecting to a U-Verse Modem/Gateway Motorola NVG 589.

• 
  -So I switch the Wifi card back to its original position where everything was running smoothly and I'm still getting the same problem
  -Uninstall and Reinstall the TP-Link drivers and the problem seems to be completely fixed. Overwatch is playing just fine, Hurray!
  -Few hours go by and the aforementioned issues come back. WTF.
  -Try reinstalling drivers again and this doesn't fix it
  -Remove the wifi card and examine it to see what might possibly be a damaged resistor on the back of the PCB and replace the wifi card with a TP-Link AC1900 Archer T9E pcie card
  -Get it installed with correct drivers and problem still persists.
  -Maybe the router's WIFI is dying?
  -hook up my old Linksys E2500 router to the U-Verse gateway via ethernet and connect through the Linksys' wifi
  -Issues completely gone. Pings a little higher but everything is running smooth as silk
  -But a day later, exact same issues. FML
  -Both routers are exhibiting similar behavior
  -Check U-Verse wifi using my Surface Pro 3 and it's 100% nominal
  -Check U-Verse wifi using my Phone and it's 100% nominal
  -Check U-Verse wifi using my desktop and I'm getting half the download speed I should be getting and 5x the ping
  -enable VPN to see if I'm being throttled and now I'm getting half the download speed with 10x the ping
  -Test ping on SP3 using 'ping -t router IP' and its a rock-steady 6ms
  -test ping on Desktop with same methodology and it's running at 3ms but ever 10 seconds, it'll jump up to around anywhere between 60ms to 200ms and then drop back down 3ms before spiking again
  -Run 3 different antivirus scans on desktop and they're all negative
  -Check for background downloads and nothing is downloading
  -Start clearing out any non-essential program that might be trying to contact a server
  -Nothing seems to lead me in a direction that will solve this issue

So it seems like the problem is within my Desktop, not anywhere else in the network. Now, I'm running a Z97 system with an i7-4790K, video card, and a m.2 SSD for my OS. I'm starting to wonder if its an issue of trying to run too much off the PCIe lanes. Maybe changing the slot would cause my motherboard to change how it prioritizes PCIe bandwidth so now the wifi card is getting the lowest priority, thus the greatly diminished performance? I don't think it's an issue with interference because I've been using a similiar setup for ages with zero issue and the problem had only arisen after I tried swapping the wifi card's pcie slot. If it's not that, could it possibly be that the PCIe slots are damaged somehow? Anyone have any idea on how to solve this issue? I've been trying to diagnose this for almost a week now and it's frustrating beyond belief.

 

[SinxarKnights]

It does sound like interference though. When you moved it did you put the power cords back the same way they were before? Did you do anything like tidy up the cabling behind the PC after moving the card?

Basically make sure there are no coils of wire near it (esp power cables) and try moving everything as far as possible away.

Is there any pattern to the issue? For example, could it be the neighbors using a microwave nearby? Have you switched channels or checked the noise floor when you are having issues? Have you actually checked for packet loss yet when having the issue?

 

[Ellis_D]

It does sound like interference though. When you moved it did you put the power cords back the same way they were before? Did you do anything like tidy up the cabling behind the PC after moving the card?

Basically make sure there are no coils of wire near it (esp power cables) and try moving everything as far as possible away.

Is there any pattern to the issue? For example, could it be the neighbors using a microwave nearby? Have you switched channels or checked the noise floor when you are having issues? Have you actually checked for packet loss yet when having the issue?

There's absolutely no pattern here. I've double check to make sure no unauthorized devices are on the network and even removed my bluetooth dongle to take any possible interference from that out of the equation. I've never experienced wifi issues like this before and it only started after I swapped my wifi card from one pcie slot to another. Unless my neighbors started running a radar beam 24/7, this really wouldn't make sense as interference.

As for packet loss, I've only seen it when pinging external websites like google and it's infrequent so I'm not sure what I could read from this. Typically the first ping will come back as a time out but all subsequent pings will act as normal with the only packet loss coming from that first ping. I've also tested this with my SP3 and it's exhibiting the same behavior.

 

[Ellis_D]

Okay, I was finally able to solve the issue. Apparently it's a bug in Corsair's Utility Engine software. There are a few .dll files that completely mess up wifi for some people and this is what was doing it for me.