Slow web page loading and connection speeds with Airport Extreme

I tried connecting my iMac directly to the cable model (Arris Surfboard SB6183), and there is no problem. Download speed was 300Mbps and upload 30Mbps.

I then hooked up my Airport Extreme router again, and connected the iMac to the router via Ethernet. Download speed dropped to 100Mbps!

There is a known compatibility issue with the Arris / Motorola SB61XX-series of modems with the AirPort base stations. Neither are bad by themselves, they just don't "play nice" together.

The other issue is a number of ISPs are slowing pushing out IPv6. Something that might help is changing all of your AirPort base station for IPv6 - Link-local only. You would do this with the AirPort Utility, as follows:

• Run the AirPort Utility, select the base station, and then, select Edit.
• Go to the Internet tab > Internet Options...
• Change Configure IPv6 to: Link-local only
• Click on Save, and then, click on Update.
• Allow the base station to restart.
• Repeat the above steps for each of your base stations.

I bought the Motorola because I read that it was the best choice for fast internet connections like the 250Mbps I have. I see a few other modem recommendations for fast internet connections, including the Netgear CM600, Zoom 5370 and SCM D3CM1604. All are compatible with Comcast and are well-reviewed. Do you have any idea if these work better with the Airport Extreme?

I would suggest the Zoom 5370. Again, the Motorola is a very good modem, it's just not compatible with the Extreme and unless you came to a forum like this beforehand you wouldn't have known.

Or would it be better to get a different router and keep the same modem? Routers are more expensive than modems, and I'd prefer to stay within the Apple ecosystem with the router if there's a modem that is more compatible with the Airport Extreme.

That's a great question! It really comes down to your overall networking requirements. For example, if security is your top-most criteria, you may want to consider routers from other manufacturers. As an example, a number of routers have more sophisticated features to meet those goals. FWIW, I use a Cisco RV180 as my "main" router and use Apple base stations to provide my wireless network.

BTW, is it unusual to see such a significant drop in speed from: direct connection to modem > ethernet cable to router > wireless connection to router? i.e. to go from 300 Mbps > 100 Mbps > 30 Mbps?

Typically, yes. However, if the modem & router are incompatible, this would not be unusual in this case.

I tried the IPv6 suggestion you mentioned and it didn't seem to affect download speeds.

Would the best next step be trying a new modem?

It was worth a try, but it looks like the incompatibility issue is the culprit. I believe I answered which would be best in my last reply.

My first priority is speed. Of course I care about security, but between the two speed is more important to me if we assume that most of the routers we're talking about have reasonably good security.

For "speed" you want a router that has excellent WAN-LAN interface and wireless throughput performance. You can get a better idea to choose from by going to a site that tests them. I would recommend SmallNetBuilder for that. You can then compare the AirPort Extreme vs. the Netgear and other router. Note: The Cisco RV180 is a wired router; it does not have wireless capability. Mine is in an enclosed cabinet with the modem where I would not want wireless anyway.

On that same review site I linked to earlier (Wirecutter), they suggested the Netgear AC1750 router. I wonder if there's any advantage in terms of compatibility in using a Netgear modem (CM600) and router (AC1750)? Again, both are well-reviewed on Amazon and elsewhere.

For compatibility, it would hard to go wrong using equipment from the same manufacturer when possible. The only caveat is that the modem should be one that your ISP supports.

Can you link me to instructions for using something like the Netgear AC1750 or Cisco RV180 as a "main" router, and then the Airport Extreme for the wireless network?

Sorry, I'm not aware of any set of instructions for that. My knowledge comes from experience with setting up networks. Again, the key here is your overall networking goals. If you stay with an Apple product we can certainly assist you with setting it up. When you get to a point where you made a decision on the networking hardware, just start a new post. I'm sure you will get help if you need it.

Also, I probably should have mentioned this before, but there is a complicating factor. I had a Sonos home audio system installed in my home. As part of that, we had two Araknis Wireless Access Points installed—one in the kitchen and one in the living room—to extend the signal through the house.

Yes, that would have been helpful. Although they wouldn't have anything to do with the incompatibility issue we have discussed.

I don't think that these access points can extend the wireless range of your Extreme, unless they are all interconnected back to the Extreme by Ethernet. This is known as a roaming type network. If they are wireless only, then they may be causing Wi-Fi interference with the Extreme's network.

These access points are indeed connected by ethernet. That's why I'm wondering if they could be slowing down the overall Wifi connection. My Airport Extreme is 802.11ac, but these WAPs are 802.11a/b/g/n. Is it possible that they are reducing the speed of the Wifi network (i.e. speed can only be as high as the lowest common denominator)?

Two things: 1) I am assuming that you have these WAPs configured as a roaming network with the AirPort Extreme. That is, they are all broadcasting a Wi-Fi network using the same network name (aka, SSID) and use the same wireless security type & password, and 2) Potentially only 802.11ac devices may be impacted, not the overall Wi-Fi network due to a "mix" of radio modes. Remember the Extreme is also capable of supporting the older 802.11 standards.

Would getting new 802.11ac access points make it faster? These seem to get pretty good reviews.

The key here is that all your wireless devices must be 802.11ac to realize any potential speed benefit. Also, since 802.11ac is only operational on the 5 GHz band, it also is subject to that band's limited range. Therefore, 802.11ac clients work best when the are in the same room as the 802.11ac WAP. For overall performance, Ethernet is still the best way to go.

My current plan is to get a new router first, test that, and if speeds are still low on Wifi, upgrade the access points. What do you think?

Sounds like a reasonable plan.

Of course if I have a new router the Airport instructions won't be valid, and I guess I'll have to find directions for doing it with the new router's software?

That would be a correct assumption ... but the overall set up would be the same. The major difference is that you would be using a web browser, instead of the AirPort Utility, to administer these non-Apple devices.

Given this, it sounds like 802.11ac capable WAPs may indeed provide better speeds.

The following table represents potential data rates for 802.11ac. Note: Both the number of streams and the channel widths the device is capable of determine this potential. The 802.11ac Extreme uses 3 streams @ 80 MHz-wide channels.