Comcast XFINITY → [Speed] Speed drop at certain time of day

Hi all! I'm located in Lafayette, Indiana and just upgraded to Blast! speeds (50 down/10 up) a little over a week ago. Everything has been pretty great and I have gotten a little over 50 down for most of the time, but here lately I have been experiencing tremendous slowdowns in the evening. It starts around 4 or 5pm in the evening and lasts until sometime after midnight then it goes back to normal. During this time frame my download speed (via speedtest.net or comcast's speedtest) will go down to as little as 6mbps, but the upload speed never goes down below 11 which is normal. I have noticed this happening for the past week and have contacted Comcast via their support chat, but haven't really made any progress.

My setup is a Comcast wireless gateway that is in bridge mode so I can use my own router which is an Asus rt-n56u that has the latest firmware. I have tried resetting the modem, resetting the router, hooking directly to the Comcast wireless gateway, changing the firewall on the wireless gateway from medium to low, and even switching the coax cables around. Tonight I contacted their support chat again and the tech there was extremely helpful in trying to determine what was wrong by having me run multiple speedtests, changing stuff on their end, running diagnostics, etc. Nothing worked so I ended up having schedule a tech to come out tomorrow, but the only time he can come is between 2p-4p which I imagine the internet will be fine during that time like it usually is. I guess I will just explain everything in detail to him and have him check the connections, but what else can I do? Anyone else in this area noticed anything like this in recent days/weeks? I know in the evening more people are probably on the system, but would/should that cause my speeds to drop so drastically from 50 download normally to, at times, 6 download? Thanks for any suggestions you may have and thanks for taking the time to read this.

It sounds typical of being on an over subscribed circuit. At 4 PM in your area you likely have kiddies coming home from school, followed by adults getting home from work, and the streaming and downloading begins, overloading the available circuit capacity.

This was very typical in my neighborhood on CC, with DS speeds in the 1.5Mb range in the evenings until DOCSIS 3 came along.

Yeah I kind of figured it might be because of capacity, but shouldn't there be something that CC can do about this? Surely you would think they would have a few measures in place to reduce the drastic reduction when more people come online. Thanks for your reply.

Do you rent or own your modem & router?
What's the model # on the modem/router?

We rent it from Comcast and it is a SMC Networks smcd3gnv. We have it in bridge mode so we can use our own router for wifi and routing which is an Asus rt-n56u.

You say you "upgraded" a week ago. What package were you using one week ago and did you also experience these exact same slowdowns?

Although on the surface this seems like an over subscription issue, I have a difficult time believing that area became over subscribed on the same day you upgraded to a higher speed package.

I apologize it was more than a week ago. We originally had the Performance package which was 25 down/5 up and upgraded to Blast! which is 50 down/10 up. I didn't really notice and I must say that I didn't really pay much attention to the speeds all the time we had Performance, but for the past week I had noticed a slow down during the 4p - midnight time frame.

We had a tech come today and he went through multiple steps trying to figure out the issue. I do utilize MOCA adapters for another computer so we eliminated those because he said they were causing noise in the line and he didn't have a high pass filter with him. He checked all the lines coming to and from the house and all were fine. There was an issue with the wrong boot file being pushed to the modem, but he got that resolved and it still was giving half the speed we should be getting. The final thing he tried was replacing the modem, but that didn't help either. The whole time he was here he was getting anywhere from 20-30mbps download instead of the 50 like he said we should be seeing. He didn't have any answers other than to come back tomorrow with an eMTA modem instead of the wireless gateway that we have been trying. Guess we'll see if that is the issue in the morning!

Well I've still been dealing with the speed issues and it seems like today is worse. Just did a speed test on a computer that is hooked up via ethernet (not wifi) and here are the results:
»stage.results.speedtest. ··· 4844.png

Keep in mind I have Blast! internet...or do until evening time frame. I have attached my modem signal levels if that will provide any assistance, but I think they are fine. I just find it really hard to believe that my internet can take such a massive hit in speed in the evening time and Comcast refuses to do anything about it. Does anyone have any other advice short of just fighting with Comcast some more? Thanks.

IIRC that's a 4x4 modem
go get a SB6141 its a 8x4
and if your having the SMC bridged it'll be best to go to a less likely to suddenly get messed with setup (there are reports that CSR's are told to take any gateway that's in bridge mode out of bridge)

The tech that came a long time ago swapped out the SMC for an ARRIS TM722G which is what we use now so it is a dedicated telephony modem so we can use our own router (Asus rt-n56u). Have to use a telephony modem because we have Triple Play and use Comcast phone service.

just googled and seems the TM722G is a 4x4 so keep that in mind if the problem continues

Yeah I see that now. I wonder why the tech would install that modem if I was having the issue in the past and that might be attributing to it? It happens every single evening at the same time and lasts until a little after midnight then will go right back to getting the full speeds of 57 download and 11 upload until the next evening where it will repeat the cycle. The tech said it was probably congestion and that there was nothing he could do about it which I guess seems understandable, but maybe he should have escalated it to someone higher up. Guess I'll just have to contact Comcast again either over the phone or via chat and see if I get someone else that is willing to do some more for me.

Well if it is congestion and if your area has 8 downstream channels then a 8x4 modem might help as it would be able to connect to more downstream channels to help avoid congestion.

That does make sense. I'll just have to ask them about it. Thanks for taking time to help me out, I appreciate it.

EDIT *12:16 AM*: »stage.results.speedtest. ··· 2004.png
Speeds back to normal lol