MacBook Air - Slow internet speed

Question

Level 1

25 points

MacBook Air - Slow internet speed

I have been using my MacBook Air for the last 4 years and it works with no issues. Till yesterday, I had no problems with its speed - with or without internet connection.

From today morning, when I connect it to internet, the net connection is very very slow - it is in the range of few hundred Kbps. I have an internet connection of 100 MBps and I checked with other laptops, my iPhone, my iPad and there is no issue with the ISP or wifi router as other devices give a fantastic speed. Only my mac air is not able to connect at high speeds. It loads a simple page after 10 minutes or so.

I cleared all cache, cleared safari temp files. Rebooted the machine.

My disk is only half full. I don't run any crapware / anti virus.

Please help me. Thanks in advance.

MacBook Air (13-inch Mid 2013), OS X El Capitan (10.11.3)

Posted on Mar 19, 2018 4:43 AM

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Answer 1

Tesserax

Level 10

155,066 points

Mar 19, 2018 10:41 AM in response to rkravi

In my experience, if even other devices do not have an issue with a particular router, it is still good practice to rule this out ... but it's certainly your call.

With your MBA as close as possible to this wireless router, please provide the following values from the Wi-Fi icon on the macOS menu bar. Note: Hold down the option key before clicking on the icon to get these values.

Security
Channel
RSSI
Noise
Tx Rate
PHY Mode
MCS Index

Now relocate your MBA to where you normally use it, and note the same values again. Please post your results.

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Answer 2

Tesserax

Level 10

155,066 points

Mar 19, 2018 10:23 AM in response to rkravi

I recommend that you start by powering-down your Internet modem/router/gateway device. Leave it powered-off for at least five minutes. Then power it back up. Wait at least 5-10 minutes to allow it to initialize, and then, try connecting to the Internet again to see if the speed improves.

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Answer 3

rkravi Author

Level 1

25 points

Mar 19, 2018 10:28 AM in response to Tesserax

Thank you for your response.

This router is shared by many others and they don’t have any issue with the speed and infact all of them get around 80-90 Mbps speed and only I have this issue since morning.

As explained in my post, I have tried this with my other laptops, iPhones and iPads and all of them have no issues and experience high speed of internet connectivity.

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Answer 4

rkravi Author

Level 1

25 points

Mar 19, 2018 11:46 PM in response to Tesserax

Thank you very much for the reply.

I did a restart of the router. And I couldn't see any improvement.

I sit very close the router and hence taken only one reading.

Here are the readings:

Security: WPA2 Personal

Channel: 149 (5Ghz, 80Mhz)

RSSI - 46 dBm

Noise - -92 dBm

Tx Rate - 585 Mbps

PHY Mode - 802.11ac

MCS Index - 8

Hope this helps. Appreciate your help in this regard.

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Answer 5

Tesserax

Level 10

155,066 points

Mar 20, 2018 8:48 AM in response to rkravi

With an MCS Index value of 8, your MBA is connecting to this 802.11ac router only using 2 spatial streams. Your MBA should be capable connecting with up to 3 streams on a 80MHz-wide channel. 3 streams would support a data transfer rate up to 1170 Mbps vs. the 585 Mbps your MBA is getting now.

I would suggest that you try connecting your MBA to other Wi-Fis and take these same measurements to compare against.

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Answer 6

rkravi Author

Level 1

25 points

Mar 25, 2018 6:25 AM in response to Tesserax

Thank you for your reply.

I took these measurements with my home wife router. I have a 100Mbps connection at home and I was the only one connected to the router when I took these measurements. Fast.com showed 40Mbps as internet speed. I normally get over 100Mbps in this router. Some issues?

Security: WPA2 Personal

Channel: 13 (2.4Ghz, 20Mhz)

RSSI - 55 dBm

Noise - -98 dBm

Tx Rate - 145 Mbps

PHY Mode - 802.11n

MCS Index - 15

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Answer 7

Tesserax

Level 10

155,066 points

Mar 25, 2018 9:16 AM in response to rkravi

In this case the MCS Index of 15 for a 802.11n connection still does not achieve the highest data rate possible. Like in the first case, your MBA is only connecting with two spatial streams on this channel ... which is only 20 Hz wide. This would reflect the 145 Mbps Tx Rate.

The only thing I am not sure of at this point, is if a 2013 MBA is capable of connecting with three streams. If it doesn't then, there doesn't appear to be any issues as far as I can tell ... but if it does, then it may be possible that the built-in Wi-Fi card on your MBA may be faulty.

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Answer 8

Tesserax

Level 10

155,066 points

Mar 25, 2018 9:54 AM in response to rkravi

Doing a bit more research the 2013 MBA included the Broadcom BCM4360 wireless card. Although this card was capable of 3x3:3, it was limited on this model to 3x3:2. That would limit its max Tx Rate to 877 Mbps for an 802.11ac connection.