Internet speed testing at different NOCs for slow performance

Where to start...

1) Plug the computer running the test into a router via Ethernet cable, as many router wifi chips... just don't work properly...

I never use router wifi hardware. I always put the router in bridge mode + disable all wifi + connect my own wifi hardware.

2) You can't really rely on SpeakEasy or any service to give you any useful numbers.

Best guess is use something like https://SpeedTest.net picking a test instance known to be fast, like Softlayer in Dallas, TX or some other know fast test instance. You learn/determine fast instances by doing a bunch of speed testing.

3) You don't ever say the actual location of your customer... which is essential to even guess what speed test results you'll get... because... some Comcast connections out of some cities are very slow, so...

You'll see fast speeds using Comcast test instances + slow speeds using any other test instance.

4) One sure way to test is to setup your own test instance at a known high speed provider, like OVH... where hardware is cheap + they're connected to the primary backbones (fast net pathways).

If you're having performance issues, ALWAYS test with an ethernet cable connected directly to the ISP's equipment. This will tell you at the very least if the issue is starting from their end. Plus you have a strong case when you're contacting the ISP for troubleshooting.

I agree with David re: using Speed Test rather than SpeakEasy. Additionally, Comcast has their own Speed Test servers: https://speedtest.comcast.net. Test both at the Speed Test site and on Comcast's site, then see what you get. (Note: You're going to get comparatively good results with Comcast's because the test is solely within the Comcast network. If you get bad results here, then you REALLY know there's a problem)

My question is this. Does Comcast or for that matter any provider determine which NOC a router goes to by default or is it configurable somehow within the browser?

You cannot configure this in the browser. It's a Comcast thing.

And likely most people will dance around what may be the main issue...

You're using Comcast.

Seriously, if there's any other option, usually other options are light years better. Sometimes worse. Usually better.

Thanks for your input guys and I really do appreciate it..
As I mentioned in my explanation I had already connected the computer directly to the router with an Ethernet cable. I noticed an immediate difference as I knew there would be however for some reason Miami was still very slow relatively speaking even with ethernet which is why I decided to come on Experts to find out about the "default" NOC and how it was controlled. From what I saw, as long as it was defaulting to Miami it was going to be slow regardless of how I was connecting to the router. (Thank you for the input on the NOC  being a "Comcast thing" masnrock. That's one of the main things I wanted to know before moving forward.)
My next step will be to run Speed Test that David mentioned. I've never used that before I don't believe but I did run two other vendor tests, actually 3 counting Comcast which as you know is nothing but bs.

 My customer is in Jacksonville Florida about 20 miles away from where I live. We both have Comcast and while I'm not getting the speeds that I'm paying for, they're acceptable for me and a lot better than hers. And that's the best way I can describe Comcast in this Northeast Florida market. I've been doing this for over 10 years here and I've only had one other instance with Comcast  with both wireless and Ethernet being slow(er). Since you know Comcast then you know that I've obviously had a lot of instances where I've had to bridge the Comcast modem and use another wireless router always with success but both Ethernet and wireless connections is rare.

I think what I'm going to do is have them purchase a different Comcast approved modem. I initially thought that I would tell Comcast to send them a new one but since they're paying monthly for the Comcast "leased" modem they'd probably be better off to try a different one altogether.

If that doesn't work I'm going to recommend that they change carriers because at that point they wont have anything to lose.
I'll post back my findings by this weekend just to give you guys an update.
(If you can think of anything else please don't hesitate to let me know).
Again, thank you very much for your support. You both were great and you both helped.
As always I not only get great responses on Experts Exchange, I also learn something.

Is your client a home user? Regardless, but in calls to Comcast. After a few tries and failures on their part, escalate to the director of operations for the county with a certified letter detailing what's been happening. That should get some attention for sure.

Yes they are a home user. They have a son who lives relatively close and he changed to a different modem and started getting better speed so  I've already asked them to get the make and model of the modem he purchased.
I'm going to give them the options of getting a new Comcast modem first or getting a different vendor modem first. If the different modem or a new Comcast modem doesn't work (with a new wireless router) then I will elevate the complaint like you say. I'm sure that by that time they will understand that it is the only option left with the exception of changing providers.
I hate to see anyone go through this crap especially when they're paying a premium for the services.

I will start trying to dig up the Comcast hierarchy in this area now so that even if one of the other options is successful I will have it ready for another customer because I know I will see it again.
Thanks again for your help masnrock. Once again I really appreciate it.

That's fair. Comcast does have a list of support modems available online. Check through the list as well.

So to fill you in with the background of the time I escalated with Comcast (and to be fair, this was years ago)...

They screwed up my install. I had ordered the Triple Play, but when they came out, they installed only two of the services because supposedly the order for the phone got cancelled. When I contacted them to sort it out, I had wanted to port my number. They didn't ever respond after a month, and when I called in, I ended up on hold for 3 hours only to find out they couldn't port my number (a simple update would've been nice, right?).
My internet was slow. A tech came out, who claimed everything was fine. Another tech came out, and said they fixed the issue. Turned out they disconnected one of my outlets, but I still had problems.
I wrote a detailed letter that I sent certified, and two things resulted:
1) I got a free month of service
2) A senior technician was sent out, who ended up finding it was a signal issue starting from somewhere on Comcast's network. I left for a trip a day or two later, but it did get fixed while I was gone.

That's a shame it happened but its good to know. You know as well as I do that all that needed to occur was for the first or even second tech to admit that they couldn't solve your problem and elevate it right then and there. I don't know if it reflects on their pay or not though which is why they don't do it.

I just talked to my client with the problem and they want to go with a different modem first and give that a shot. If they try it and it doesn't change anything then they can take it back and we'll go to a new Comcast modem. If that doesn't get it then it's time to go upstairs.

Just an FYI, I was at a client last week and a Comcast tech had already been called and while he was there I talked to him about their modem/wireless problems and he told me that they have a new modem that they're installing now that's better than anything else they've had. I thought it was bs at first however I found out that it's probably true.
 I had hooked up a separate wireless modem for this guy years ago so that they could get adequate coverage and it has served them well however after the new Comcast modem was hooked up and configured that day I held off on the other wireless router and didn't bridge the Comcast and lo and behold they're getting coverage all over the place now and there's no longer a need for a separate router.
Maybe after a couple of decades they're getting the message.

Thanks again for the input and help masnrock.  I'll post again hopefully by this weekend to  let you know how this plays out.

Any progress?

As a matter of fact, maybe. I was with the Comcast tech remotely when he came out and showed him what I was up against. He plugged in his speed test on his device I presume which wasn't the Comcast test and it immediately defaulted to a server at a University in the city showing reasonable speed but certainly not what they were paying for. He finally switched from 2.4 to 5 and the speed went up considerably. Unfortunately their nic didn't support both channels. I'm not sure  why  my  speed test defaulted to Miami but apparently it was because it only used major NOCs. Do you know If I used a wireless adapter if it would pic up both 2.4 and 5? What do you think about everything? And thanks for the follow up Masnrock. Since the question has been pulled if you want to text by all means do so (if it is legal) 9045401617