After moving to a new house at the beginning of November, me and my brother had decided to upgrade to Gig speeds when we transferred our service. The day we moved in, I had installed a temp line to our old (XB3) modem since the new house already had a drop and screw being without internet while waiting for a Comcast tech. For the couple of days we ran off the XB3 with the lower speeds (Blast 200/10 iirc), everything was working perfectly. No issues playing games (WoW mainly), streaming, etc. but everything changed (when the fire nation attacked?) when the tech came out, installing the XB6 (swapping to the Gig speeds with it) and a couple X1 boxes.
First of all, the tech was horrible. Ran the lines to wall plates inside the home, but left about five feet of extra coax hanging on the outside of the house at both plates. On top of that, he just screw'd the plates directly into the sheetrock without anchors so obviously they fell out of the wall within a day of him putting them in and he did a bunch of other stuff that completely butchered the install. Back to the main story though, the next couple of days the internet was horrible. Playing WoW, there would be constant latency spikes. Going more than 10 secs without one seemed like a miracle. So onto tech #2 coming out. He took one look at how the previous tech left everything in, called the guy not even close to intelligent(paraphrasing because calling him anything worse isn't allowed here apparently), and then proceeded to completely redo the install. He also removed three cut lines from the tap after I mentioned that they could be causing noise to it. So at this point, everything but the drop (which was ran according to Comcast BRIS) was brand new, RF levels were all within spec, and the latency issues were not even noticeably improved.
The issues aren't specific to a single device, both my brother's macbook and my less than 2 year old, built for gaming, PC hardwired to a gig compatible NIC have the same issue when doing any kind of gaming. From my own personal research, the two most likely culprits seem to be:
1) An issue with the chipset in the XB6 which the sources are from late 2016, early 2017 so I'm unsure if it has been resolved.
2)Bufferbloat which again, I'm unsure if the XB6 has software built in it to help prevent it considering finding that out is a bit out of my league.
The most common fix for both issues is to fork over large sums of money for my own docsis 3.1 compatible modem and high end router, but I'm hoping to avoid having to drop a couple hundred dollars to fix a problem when the "upgrade" is what busted everything up in the first place.
I'd greatly appreciate any assistance in fixing this before I have to revert to my old 200/10 connection for now just to get consistent internet access.
Edit: Testing pings shows between 2-10% delayed (300+ms) or lost packets consistenly and DSLreports testing shows spikes up to 3k ms for upload bufferbloat and significantly lower, but still higher than average bufferbloat on the downstream.
The speed test you have mentioned are you running these hardwired or wireless? the XB6 is a dual band Gateway offering a 2.4 and a 5Ghz networks, are your networks broadcasting a seprate network names or do you only see one wifi name?(depends who you talk to you will get a differen anwser but with past experiance it better if you have 2 seperate networks) If your testing usung Wifi how far are you away from the Gateway? Keep in mind the XB6 is built for speed not range, you will see wifi coverage decreased If your using the 2.4GHz network compared to the XB3. Is the XB6 in the same spot where you put the Xb3?