VERY SLOW UPLOAD SPEEDS, download is fine.

It's not letting me post my modem stats...but power on downstream goes from 2.1 to 9.4 dBmV. All 32 channels are locked. SNR is around 37 dB on all. No correctable codes. Upstream goes from 47.5 dBmV to 49.5 dBmV on 4 channels that are locked. There are 4 more channels that are not locked, however. But cox said that those 4 do not need to be locked for some reason. Also not sure about OFDM and OFDMA channels but i have 2 for downstream and one is locked and 2 for upstream and neither one are locked. 

Thanks. I've used speedof.me, speed test.net, testmy.net, cox.com...all showing low. I will try the guide.

This guide is just for a single PC, correct? I'm having slow upload issue on every PC, laptop, xbox, phone I have. 

I tried it on my main gaming pc and it worked for me. and I have done it on my second pc and i got some good results. For me I was getting strong wifi speeds but not lan speeds. So I did some research and complied everything that I did to get my speeds to stabilize. 

I gotcha. I'm getting slow speeds all around, including wifi. Last tech found slow speeds at the pole. It's something with the lines coming to my house. Lineman said he found something and fixed it, and my speeds were good for a few days, but went back down now. 

There was suppose to be some linemen come out again to check the lines again this week, but I haven't heard back anything yet. 

with ping plotter, you have to watch for packet loss in the cox hops, then look for packetloss on the very last hop. also check your upstream and downstream signals, Good Downstream power level are within -7 to +7 dBmV. Good upstream power levels are within 38-48 dBmV. if you dont know how to see that, go to 192.168.0.1 (if you are using a cox modem/router) not too sure how to do on an aftermarket router. Click "Connection" and go to "Cox Network" and scroll all the way down, and find Downstream and upstream power levels. and check if they are in those ranges.

Thanks Zurq, always some good info.  My Netgear C6900 had 24 channels, download power -8.9 to -13.8.  My upload had 4 with results of 48.4 to 50.4.  So by your standards of +-7 and 38-48, I'm outside the ranges of being Great, maybe Fair.  The Home screen shows the Cable Connection as Good.  Is there a Better, Great or Excellent indicator here?

I've tighten my modem coaxial connection, including the 1 splitter, and wall, and have power restarted the modem.  Does this imply my Modem is going bad, one that I purchased but on the COx list.  Since I don't really have issues, other than noticing my upload speeds dropping to half the 2week ago numbers when using the COX speedtest.  Other speed test give higher uploads.  Also did a pingplotter to the cox site, and showed #6 with lager packet loss.  But Cox said my modem had issues, and did not want to discuss the Hop issue I saw.  Cox also would not share the IP address that their OCounty speed test was pointing to so that I could have run a ping or pingplotter  to it instead of speedtest.  WinMTR also had same #6 PLoss like pingplotter did.

by your power levels your modem seems to be running well. If you have a cox modem i'd just go to the cox store and get a new one just to rule it out. I added my own router instead of using the cox modem/router, and make sure if you do have a cox modem/router combo you must put it in bridge mode, it works best for me if you do. and Cox has been effed up for a while if I run a speed test on cox servers it gives me 5 upload it must be something on their end, also turn qos on your netgear router. it helps.  and if you want to be 1000% sure it's their end if you are under warranty replace the Netgear C6900. and if you want to test ever further test the speeds and ping plotter wtih the panoramic modem/router. then build a case and escalate it to COX or the FCC make notes take screenshots, so you can show them it isn't your equipment, nor anything you are doing wrong to impact the Quality of the Service.

and if you run a speed test, open up task manager, and go to performance and click network and the send and receive speeds are your upload and download and it should show correct speeds. if it doesn't then you might have a hardware problem.

Zurq...wealth of info...now my numbers of -8.9 to -13.8 and 48.4 to 50.4 are outside the ranges you posted, but you implied my power levels are running well....really?  Do you know if there are better indicators on the Netgear main panel...mine said Good.  My c6900 is my modem/router purchase.  I don't understand 'bridge mode', and yes, it seems like a Cox prob since it only started recently down to about 4-6 upload.  Also, 'qos' I'll take a look again in forum, seem to have seen this notation.

I will also take a look at task manager...that should be fun.  As I said, pingplotter to the hop#6 to cox.com from my ip definitely shows %Ploss...If you have pingplotter or WinMPR, check the hops to cox.com.  Also in the Cox speed test, try to go to OC server...you may be on the other side of the country so your numbers could be anything....especially if you are getting in 5's for upload.

I did a  cmd ping -n 20 cox,com and got Zero %packet loss, but pinplotter, which checked the hops did find #6 loosing 30%...  Curious

Update...did a taskmanager view of performance/ethernet and then engaged the cox speed test to my OC area...task mgr gave high of 248 while speed did 220+...but the upload had taskmgr 11.2 max, and cox speed test had around 6...good tool Zurq!