Moved to Comcast Gigabit up from 200mbps, but getting slower speeds pretty much across the board.

[malrats]

So, I "upgraded" to Comcast gigabit internet today. Previously, we had 200mbps from them. That was perfectly fine by all of my standards and I always hit at least 230-250mbps on all speedtests and could download at around 24-28 mb/s. It was great. I'd get that speedtest result on both a laptop and desktop with a AC1200 adapter and on my iPhone X, among other devices.

Yesterday the "upgrade" happened and we were bumped up to gigabit. The first DOCSIS 3.1 modem wouldn't get a connection, so we had to borrow a Xfinity 3.1 Gateway until we could buy another. The gateway, of course, activated and worked without issue, aside from its bridge mode refusing to play nice with my router (Linksys AC5400 EA9500, really nice router by my standards) and I was either stuck with no IP or internet access, or I'd have to turn off bridge mode and get stuck with a double NAT.

Today Comcast came out and put in our replacement modem, which was a SURFboard SB8200. There's a pad on the back that got the levels down from like +15-16 to +5-6, which as I recall is pretty good. I had tried to self install that modem last night and phone support couldn't get it to activate/work, but today it did when the tech was here. He was able to call into a more specialized and seemingly competent team, though, so that may have had something to do with it (it seemed like he knew the woman personally, so I think they were local).

However, this is where the real issues come in. Now, first and foremost, I understand that gigabit ethernet does not really mean (especially over wifi) that I'm going to be getting 1000mbps speedtests (though I did get a 914mbps speedtest while hardwired to my router while the tech was still here). I was not at all expecting to get some kind of MASSIVE boost to all of my devices, but rather a nice little boost to those that can utilize 5GHz and then otherwise more bandwidth to go around for the 20+ devices that are generally connected around my house.

But I was sadly mistaken. My laptop with the AC1200 adapter, for example, is now lucky to hit 150/42. My iPhone X overperforms (depending on where I am) and will sometimes get 100mbps and other times it'll get 650mbps. Depends on a lot of things, though I'm not sure of what. Everything else that I test generally falls in the same range of around 100-200mbps at best on 5GHz, and these are universally devices that were achieving 230-250mbps consistently while we were still on the 200mbps/DOCSIS 3.0 tier.

Anyone have any idea of what may be going on? This is really upsetting, beyond the fact that the price increase is pretty significant. I just can't comprehend or be content with getting considerably SLOWER speeds when paying for what's supposed to be roughly 800mbps MORE than I had before, at least on paper. I'd be more than happy with consistent gains of even 50-100mbps, and hell...at this point I'd honestly be happy with the same 250mbps speeds that I had before and just more bandwidth to go around.

Help me, tom's hardware, you're my only hope.

 

[vmfantom]

So, I "upgraded" to Comcast gigabit internet today. Previously, we had 200mbps from them. That was perfectly fine by all of my standards and I always hit at least 230-250mbps on all speedtests and could download at around 24-28 mb/s. It was great. I'd get that speedtest result on both a laptop and desktop with a AC1200 adapter and on my iPhone X, among other devices.

Yesterday the "upgrade" happened and we were bumped up to gigabit. The first DOCSIS 3.1 modem wouldn't get a connection, so we had to borrow a Xfinity 3.1 Gateway until we could buy another. The gateway, of course, activated and worked without issue, aside from its bridge mode refusing to play nice with my router (Linksys AC5400 EA9500, really nice router by my standards) and I was either stuck with no IP or internet access, or I'd have to turn off bridge mode and get stuck with a double NAT.

Today Comcast came out and put in our replacement modem, which was a SURFboard SB8200. There's a pad on the back that got the levels down from like +15-16 to +5-6, which as I recall is pretty good. I had tried to self install that modem last night and phone support couldn't get it to activate/work, but today it did when the tech was here. He was able to call into a more specialized and seemingly competent team, though, so that may have had something to do with it (it seemed like he knew the woman personally, so I think they were local).

However, this is where the real issues come in. Now, first and foremost, I understand that gigabit ethernet does not really mean (especially over wifi) that I'm going to be getting 1000mbps speedtests (though I did get a 914mbps speedtest while hardwired to my router while the tech was still here). I was not at all expecting to get some kind of MASSIVE boost to all of my devices, but rather a nice little boost to those that can utilize 5GHz and then otherwise more bandwidth to go around for the 20+ devices that are generally connected around my house.

But I was sadly mistaken. My laptop with the AC1200 adapter, for example, is now lucky to hit 150/42. My iPhone X overperforms (depending on where I am) and will sometimes get 100mbps and other times it'll get 650mbps. Depends on a lot of things, though I'm not sure of what. Everything else that I test generally falls in the same range of around 100-200mbps at best on 5GHz, and these are universally devices that were achieving 230-250mbps consistently while we were still on the 200mbps/DOCSIS 3.0 tier.

Anyone have any idea of what may be going on? This is really upsetting, beyond the fact that the price increase is pretty significant. I just can't comprehend or be content with getting considerably SLOWER speeds when paying for what's supposed to be roughly 800mbps MORE than I had before, at least on paper. I'd be more than happy with consistent gains of even 50-100mbps, and hell...at this point I'd honestly be happy with the same 250mbps speeds that I had before and just more bandwidth to go around.

Help me, tom's hardware, you're my only hope.

Here's how wifi works (and it's not at all how they market it). Your EA9500 can't negotiate 1024-QAM with your AC1200 adapter, so your max 8x8 MIMO Phy rate is 1733 Mbps at 5 GHz (256-QAM). You can't attain 1733 Mbps unless the EA9500 without an onboard PCI-e storage interface, so you'd be capped at around 940 Mbps given Ethernet frame overhead.

Next, you add CSMA delays. At least a few milliseconds for arbitration interframe spacing, a few for min/max contention windows, a few for transmission opportunity. You can't specifically edit those values in consumer grade routers, although WMM helps. But the upshot is that all the carrier sensing delays would lower throughput by around 40% of the Phy rate, which again would be adjusted by Ethernet overhead.

Then you add attenuation and its affects on the modulation. If your RSSI is much weaker than -35 dBm, you probably aren't getting 256-QAM. A wifi testing app would tell you the link rate, which you could reference at mcsindex.com.

Now back to CSMA delays. If there are any other routers or connected devices transceiving on the same channels used by your router, those minimal delays increase a lot. Instead of 31 ms for the contention window, maybe it's 1023 ms. Any delay lowers your real world throughput.

With no same-band contention and minimal distance between router and client, you might see up to 500-600 Mbps at 5 GHz. If you actually connected the router to a PCI-e adapter with jumper cables for a completely closed set of channels, you could bring it up to maybe 940 Mbps at 5 GHz. But any attenuation or interference will cause throughput to fall significantly.

You can troubleshoot this somewhat with a wifi testing app, seeing how bad your RSSI is, which link/Phy rate it's negotiating, and how many other routers/APs are hogging the same channels. But the bottom line is that wifi is a shared access protocol and you're a victim of interference and attenuation.