Apple routers, Apple devices: Poor 2.4 GHz speed (mobile devices only)

[Ichinisan]

Cliffs: Two households, both with Apple routers. Latest Apple mobile devices get poor WiFi performance on 2.4 GHz (about half speed), great performance on 5 GHz. Win 8.1 desktop PC and 2009 iMac get great performance on both bands. This is consistent and repeatable.

I really don't know whether to put this in the Networking forum or All Things Apple. It seems to be a compatibility issue, but that's very strange because the only devices that are having trouble are the latest Apple mobile devices connecting to the latest Apple router.

I understand that an apartment building is going to have a crowded 2.4 GHz spectrum. My studio loft is basically one large room with some closets, so all my devices seem to have a great signal at all times. My Apple TV (almost right next to the router, through a wall) uses 5 GHz. I usually connect mobile devices to the 2.4 GHz network because that penetrates walls better. Everything else is wired (TiVo, printer, desktop PC).

One exception to the "great signal" thing: Before I got the AirPort Extreme 6th gen 802.11ac, I had a 5th gen 802.11n model. With that one, my Win 8.1 desktop PC (wired, but 802.11ac WiFi capable) would show a very weak WiFi signal on the 5 GHz network, no matter how I tweaked the wireless settings. There really wasn't a good reason considering how small my apartment is. With the 802.11ac model, my desktop computer shows a full-strength signal on 5 GHz. Go figure... I don't think beamforming would have anything to do with this because that computer isn't even connected to the network (it's only listing SSIDs in-range). The 2.4 GHz network was always full-strength, even with the previous router.

I first noticed this with my iPhone 6 Plus connected to my AirPort Extreme (6th gen, 802.11ac). I was only getting around 20mbps on my 60mbps connection when running the Ookla SpeedTest.net app. It was consistently right around 20mbps download every single time. Upload speed was fine (right around the maximum of 6mbps).

Rebooting the router had no effect on 2.4 GHz performance. After rebooting the phone, it's getting 25-30mbps every time -- a noticeable improvement, but still half of what it should be.

I connect the same device to the 5 GHz network and it's 60mbps every time. Also tested with my iPad mini 2 (retina) and my brother's iPhone 6 Plus with the same results: 2.4 GHz network gets about half the download performance versus the 5 GHz network.

Years ago, my iPhone 4 (2010) was able to get 30mbps consistently on a 30mbps Internet connection with an old Linksys WRT54G 802.11g router. I can't figure out why a 2.4 GHz 802.11ac connection would have this limitation, especially considering...

The Win8.1 desktop PC gets full-speed on the 2.4 GHz network. It's usually wired, but I can test with the wired interface completely disabled. It gets a full speed connection no matter which network I connect to (2.4 GHz or 5 GHz). It's also the furthest from the router I've tested because it's in the corner of the room.

I confirmed the same thing at my mother's place, where there's practically no wireless interference. There, in the same room with an AirPort Time Capsule 2TB 802.11n, I tested from my iPhone 6 Plus, my brother's iPhone 6 Plus, and my mother's 2009 iMac. Both phones got poor performance on 2.4 GHz, full speed on 5 GHz. The iMac got full speed on both 2.4 GHz and 5 GHz bands.


One thing I haven't looked into:

I might have set my mother's Time capsule to "802.11n only" because my mother has no G devices (and never will). I'll have to look at it again the next time I visit. Logically, such a setting should only improve performance because it no longer has to maintain legacy compatibility with older a/b/g WiFi devices. I just wonder if this mode isn't implemented or tested correctly in Apple routers. Perhaps this will need to be corrected with a firmware update.

My own router is set to "automatic," but I will try setting it to n+ac only.

 

[azazel1024]

You phones are single stream (SISO), which means maximum of 65Mbps 2.4GHz and 433Mbps 5GHz.

Apple products are 20MHz only in 2.4GHz, which translates to 65Mbps maximum link rate. Useful yield is generally half link rate (worse in a crowded environment). My Asus T100 which is also a SISO adapter, but 11n, on 2.4GHz 20MHz I can get roughly 50Mbps on a GOOD connection. On a somewhat less than ideal, it is going to be more like 40Mbps or so.

My iPhone 5 caps at around 30-35Mbps on 2.4GHz 20MHz. Apple's 2.4GHz performance has never seemed all that great (my wife's old iPhone 4s managed about 30Mbps with a tail wind. Her iPad 2 manages about 30Mbps with a tail wind).

So that is what you are seeing, 2.4GHz 20Mhz single stream performance, 65Mbps maximum link rate, more like 30-50Mbps real performance (depends heavily on client and how clean the 2.4GHz environment is, how close to the router, etc.)

Phone wifi chipsets also tend to be crappier than a laptops or a good tablet's, which adds to the poor performance.

Your Windows 8.1 desktop on the other hand I assume probably has a 2:2 wifi chipset in it, which means 130-144Mbps link rate maximum (on 2.4GHz) with the Apple router, which should easily push >60Mbps if you have a strong connection.

 

[Ichinisan]

You phones are single stream (SISO), which means maximum of 65Mbps 2.4GHz and 433Mbps 5GHz.

Apple products are 20MHz only in 2.4GHz, which translates to 65Mbps maximum link rate. Useful yield is generally half link rate (worse in a crowded environment). My Asus T100 which is also a SISO adapter, but 11n, on 2.4GHz 20MHz I can get roughly 50Mbps on a GOOD connection. On a somewhat less than ideal, it is going to be more like 40Mbps or so.

My iPhone 5 caps at around 30-35Mbps on 2.4GHz 20MHz. Apple's 2.4GHz performance has never seemed all that great (my wife's old iPhone 4s managed about 30Mbps with a tail wind. Her iPad 2 manages about 30Mbps with a tail wind).

So that is what you are seeing, 2.4GHz 20Mhz single stream performance, 65Mbps maximum link rate, more like 30-50Mbps real performance (depends heavily on client and how clean the 2.4GHz environment is, how close to the router, etc.)

Phone wifi chipsets also tend to be crappier than a laptops or a good tablet's, which adds to the poor performance.

Your Windows 8.1 desktop on the other hand I assume probably has a 2:2 wifi chipset in it, which means 130-144Mbps link rate maximum (on 2.4GHz) with the Apple router, which should easily push >60Mbps if you have a strong connection.

I'm at work and can't read your whole post yet, but I read the first line and I'll stop you there:

My old iPhone 4 (2010) got better 2.4 GHz performance with an 802.11g Linksys WRT54G -- consistently.

This is 802.11ac, so it should be better. Not worse.

 

[Emulex]

Apple tends to avoid channel bonding on 2.4ghz on purpose. Many other brands allow this up to all channels in use. Which pisses over all usable USA channels.

Also make sure you are not near a non-USA (buffalo ahem) broadcasting router! If your macbook/iphone picks up on the foreign band terminal broadcast of another router, it will reduce the eligible bandwidth to acceptable channels.

My old buffalo router would say it was from KR (korea) which impacted the channel selections - the Apple products take the word of the first seen beacon by default. Most Windows implementations let you hardcode this to US !

you can check on a macbook by doing to terminal and running

sudo dmesg

and checking for the US band signifier!

 

[azazel1024]

I'm at work and can't read your whole post yet, but I read the first line and I'll stop you there:

My old iPhone 4 (2010) got better 2.4 GHz performance with an 802.11g Linksys WRT54G -- consistently.

This is 802.11ac, so it should be better. Not worse.

Are you positive you are remembering it right? Because 802.11g tops out around 25Mbps absolute maximum usable bandwidth. It has lower yield than 802.11n, at 54Mbps modulation rate, you'd be lucky to get half that. 802.11n on a very good connection, you might get 75% yield.

Let me remind you, MOBILE wifi chipset. The rules are not necessarily the same. Lower modulation rates also = louder signal.

This is also not 802.11ac, it is 802.11n in 2.4GHz. Just like 802.11g is not in 5GHz, such an animal does not exist.

802.11ac routers TEND to be faster than 802.11n routers in 2.4GHz for a variety of reasons, but I can guarantee they are using the 802.11n protocol when talking in 2.4GHz. So all of those rules apply.

Which means 65Mbps link rate, which is "barely" faster than the 54Mbps link rate of 802.11g...and all of Apple's mobile devices (IE phones and pads) are limited to 65Mbps in 2.4GHz, and a practical ~30Mbps.

From what you said, when you rebooted your phone, you were getting speeds up to around 35mbps, which makes it slightly faster than your old 802.11g router, if not by much.

 

[smitbret]

My first thought echoes Azazel. I don't think I have ever seen a wireless G client in the wild that got more than 22Mbps.

 

[Ichinisan]

Apple tends to avoid channel bonding on 2.4ghz on purpose. Many other brands allow this up to all channels in use. Which pisses over all usable USA channels.

Also make sure you are not near a non-USA (buffalo ahem) broadcasting router! If your macbook/iphone picks up on the foreign band terminal broadcast of another router, it will reduce the eligible bandwidth to acceptable channels.

My old buffalo router would say it was from KR (korea) which impacted the channel selections - the Apple products take the word of the first seen beacon by default. Most Windows implementations let you hardcode this to US !

you can check on a macbook by doing to terminal and running

sudo dmesg

and checking for the US band signifier!

I use the AirPort Utility for iOS. The Windows version is outdated now. The router actually does have a region selection, which has been set correctly.

Most routers will let you enable additional channels by simply changing the region, but the FCC would be pissed off at you. The ISP that I work for has a batch of Motorola WiFi cable modems that identify the region as "Romania" and allow channel selections up to channel 14. They also do not allow you to change the region.