Speed Up Your Network
What some perceive as a slow Mac may have nothing to do with the Mac itself, but rather with one or more of the links in the network between the Mac and another computer (such as a web server). In this chapter I look at several parts of that chain to help you identify and clear bottlenecks.
This discussion of network speed is deliberately shorter on details than most of this book, for two reasons:
Because of the many variables involved in optimizing a wireless network, it would take an entire book to do that topic justice. Luckily, such a book exists: Glenn Fleishman’s Take Control of Wi-Fi Networking and Security, which I recommend.
The last comment notwithstanding, a large percentage of network speed issues can be solved readily with a few simple tests and tips, which I’m happy to provide in the following pages.
Understand Factors Influencing Network Speed
Suppose something you’re doing that involves resources on the internet—such as loading webpages—seems slow. This sort of thing can be tricky to diagnose, because there may be a great many links in the chain between your Mac and the server it’s talking to, and any one of them could be the bottleneck. For example:
Your Mac itself could have network configuration problems.
Your browser, or an extension or plugin, might be at fault (as discussed earlier, in Speed Up Your Browser).
A particular process (such as an online backup app) could be monopolizing your internet bandwidth.
You could have a bad Ethernet cable. (Seriously!)
The Wi-Fi connection between your Mac and your wireless router might be too slow.
The broadband link to your ISP could be inherently slow, or the ISP could be experiencing temporary congestion.
The DNS servers that map domain names to IP addresses could be responding slowly, adding delays to each request you make.
The server on the other end—or any of the intervening routers, switches, hubs, gateways, and other equipment—might be too slow (see the sidebar When I Say “Slow”… ahead).
The problem could also be caused by more than one of these things—or by something else entirely. Some of them are out of your control, but you should be able to at least find out approximately where the issue lies, and take steps to deal with elements you can control.
The first thing to do, as with any problem, is not jump to conclusions. The way to diagnose network problems is to proceed step by step, examining each link in the chain as you go. When you find a bottleneck, you can take steps to clear it. Then keep looking, because there might be another one!
As usual, I recommend starting with a relatively clean state, removing as many variables as possible. So, before performing any tests, restart your Mac, and don’t run any apps except the ones you’re using for the tests.
In addition, as you read the following sections, keep in mind that you’re looking for the slowest link in the chain. Even if you have an old 100-megabit Ethernet network, that might be faster than your broadband internet connection. So although upgrading your Ethernet hardware may help with transfers from one device to another on your local network, it could have no effect at all on the speed of traffic to and from the internet, because your broadband connection is the bottleneck. Similarly, if you’re using an 802.11g Wi-Fi network, that’s much slower than 100-megabit Ethernet, so upgrading to a faster Ethernet network wouldn’t help. But if you’re using 802.11ac, its maximum speed can top 1 Gbps, so upgrading to gigabit Ethernet may help a great deal. And if you’re fortunate enough to have a gigabit broadband connection (or even one that’s well over 100 Mbps), 100-megabit Ethernet hardware can indeed slow everything down.
I discuss all these standards and speeds on the upcoming pages.
Monitor Network Activity
Numerous third-party utilities, such as MenuMeters (see Use Live Monitoring Tools), can give you a broad overview of network activity, showing the total amount of inbound and outbound network traffic right now. That’s interesting and useful, but if your traffic is unusually high, the important things to know are which processes are responsible for that activity and where on the internet the data is coming from (or going to). Knowing this information can tell you what steps to take next, such as quitting an app, changing its settings, or letting a task (such as online backups) run its course before starting another bandwidth-intensive activity.
Activity Monitor (see Use Activity Monitor) can tell you part of this, namely which processes are responsible for the most incoming or outgoing traffic. On the Network tab (Figure 9), you can sort by the Sent Bytes or Rcvd Bytes column to see which processes have uploaded or downloaded the most data since the last time your Mac restarted. (I recommend trying both sort orders, because an app may send lots of data while receiving little, or vice versa.) For some web browsers (including Safari), Activity Monitor even breaks down the information by tab or window, showing the data transfer statistics for each site you’re currently connected to.
However, you may also want to know the source or destination of incoming or outgoing traffic for other apps and processes. For example, perhaps a social networking app is downloading a lot of data but you don’t know where that data is coming from. Or a video app is uploading lots of data but you don’t know where it’s going. Once you collect that information, you may realize you need to change an app’s settings—or even remove it (if it appears to be doing something it shouldn’t).
To get that level of detail, you’ll need a network monitoring tool that lists the IP address or domain name of every incoming and outgoing network connection. One example of such a tool is Little Snitch, whose Network Monitor window lists all your Mac’s current connections, sorted by process name, data volume, or last activity (Figure 10). Little Snitch is complementary to Activity Monitor in that it tells you where on the internet the data is coming from or going to, not just the amount of data being transferred.
Check Your Wi-Fi Connection
If your Mac uses Wi-Fi to connect to the internet (as opposed to a wired Ethernet connection, which I talk about ahead), several factors can affect your effective network speed. This is not an exhaustive list, but the following items are worth checking and, if necessary, adjusting.
802.11 Flavors
What we call “Wi-Fi” may be any of several different standards, all grouped under the designation “802.11,” the number used by an engineering standards group for wireless local area network (WLAN) protocols. A letter added at the end denotes the particular standard (which is often referred to by that letter alone in caps)—for example, 802.11b (also known as just “B”).
These standards started with 802.11b, which was used by the original AirPort, and then 802.11g, used in AirPort Extreme base stations and adapters released starting in 2003. The 802.11a flavor, which was released at the same time as B, never took off except in corporations, and was typically used for voice-over-IP (VoIP). There followed 802.11n, which debuted in 2007 in AirPort Extreme and Time Capsule hardware and in 2008 in the AirPort Express. The latest standard is 802.11ac, which Apple first supported in Macs, AirPort Extreme base stations, and AirPort Time Capsules released in 2013. The original version of AC was referred to as “wave 1”; Apple first supported an even faster variant called “wave 2” in the iPhone 6S and 6S Plus, followed by newer Mac models. (An even faster standard, 802.11ax, is starting to appear in new products, although at publication time Apple had not yet announced any devices that support AX.)
In most cases, hardware that supports newer standards can drop down to lower speeds in order to work with older devices. For example, a brand-new MacBook Pro that supports 802.11ac wave 2 can still connect to a 15-year-old B router, although it will be limited to the speed of that older standard; likewise, the latest AC routers can be configured to allow older A, B, G, and N devices to connect.
You’ll get the best performance if you use the fastest flavor that both your Mac (or other wireless devices) and your wireless router support. (You almost never have to set this up yourself, by the way; with default settings, the equipment normally negotiates the fastest speed and standard common to the devices.) However, note that in certain situations, when a device using an older flavor of 802.11 connects to a router that supports a newer flavor, the older device can slow down the whole network somewhat—but only during the times that device is actively transferring data. This occurs most commonly when a B or G device connects to an N network. Some routers let you compensate for this problem by setting up two separate networks, each using a separate band. (I say more about this under Band, ahead.) Another approach is to set up two wireless routers—say, one for N, G, and B, and the other for AC and A only.
How can you tell which flavor of Wi-Fi your Mac is currently using? Option-click the Wi-Fi 
menu. Your current Wi-Fi network is listed first, and beneath it, in gray letters, you should see “PHY Mode” followed by the version of Wi-Fi you’re now using. (Of course, your Mac may be capable of using a faster standard; the menu shows only what it’s using at this moment.)
What you should do: If you’re using a slower flavor of Wi-Fi than AC, consider switching. This may require adding hardware to your Mac, upgrading your wireless router, or both. If your Mac itself doesn’t have built-in support for AC, you can add it using an inexpensive (around $20) USB dongle; you can see many examples at Amazon. If your wireless router lacks support for AC, you’ll need to buy a new one. Apple doesn’t sell Wi-Fi routers anymore, but other manufacturers, such as NETGEAR, D-Link, and TP-LINK, offer fantastic Wi-Fi routers at much lower prices than Apple once charged for an AirPort Extreme.
Band
The A and AC standards use the 5 GHz frequency band exclusively; the B and G standards use the 2.4 GHz band exclusively; and the N standard may use either or both of those bands. The 2.4 GHz band offers greater range but lower bandwidth—and is more likely to encounter interference from other networks and from consumer devices such as microwave ovens and cordless telephones. The 5 GHz band has a shorter range but twice the potential bandwidth—and less chance of interference.
Apple and other manufacturers of AC and N devices employ a number of techniques to eke out even more performance in the 5 GHz band. These include:
Bonded (or wide) channels, which effectively double the available bandwidth for a given connection
A technology called MIMO (multiple-input, multiple-output), which uses an array of antennas to transfer multiple streams of data simultaneously
Beamforming, which helps devices focus their radio energy in a particular direction and thus improve both range and throughput
All this means that using the 5 GHz band exclusively is usually the best choice, assuming all your equipment supports it and your wireless devices can be placed close enough to your base station to receive a strong signal. (If you have older equipment without 5 GHz support, you can usually configure your wireless router to use 5 GHz and 2.4 GHz simultaneously, but that’s suboptimal, because even newer devices that support 5 GHz often pick 2.4 GHz when connecting to routers that use both bands.)
What you should do: If you use an Apple base station, open AirPort Utility and select your base station. Click Edit > Wireless > Wireless Options. From the Radio Mode pop-up menu, choose either an 802.11ac option or an “802.11n only” option that includes the label “(5 GHz).” If you have another brand of wireless router, consult the manufacturer’s instructions for setting it up to use 5 GHz exclusively.
Encryption
To prevent unauthorized use of your wireless network or, worse, eavesdropping on your private data, you should enable Wi-Fi encryption on your base station or wireless router. In addition to the security reasons for using encryption, though, there’s a little-known performance consideration for those using N networks. (This doesn’t apply if you’re using B, G, or AC.)
An 802.11n network can use only the most modern encryption standard, called WPA2, which comes in personal and business (enterprise) flavors, and which went into wide use in 2005. WPA2 Personal is what you should use on a home or small office network. If you instead pick the older, broken WEP standard (which dates to 1999) or the original WPA Personal flavor (released in 2003 as a stopgap improvement), your base station cannot use N networking. Instead, it silently reverts to G, dropping your maximum network speed by as much as 50% to 75%. (Apple explains this phenomenon in the article AirPort: Slow 802.11n connection speed when connected using older WEP or WPA security mechanisms.)
What you should do: To check or change your AirPort base station’s encryption method, open AirPort Utility and select your base station. Click Edit followed by Wireless. Choose WPA2 Personal from the Wireless Security pop-up menu, enter and confirm a password, and click Update. (Note that you also get N speeds if encryption is disabled, but I strongly recommend using encryption.) If you have another brand of wireless router, consult the manufacturer’s instructions for setting it up to use WPA2 encryption.
Signal Strength
All things being equal, the farther your Mac is from a wireless router, the weaker the signal will be. There is no hard and fast correlation between signal strength and network speed—that is, you may get the maximum throughput even with a less-than-full-power signal; conversely, you could have great signal strength but so-so throughput. But in general, the likelihood of poor throughput tends to increase as your signal strength decreases. Distance from the wireless router, obstacles (including walls and floors), interference, and other factors can influence your signal strength.
What you should do: To see your current signal strength, Option-click the Wi-Fi menu. Your current Wi-Fi network is listed first, and beneath it, in gray letters, you should see “RSSI” followed by a negative number, which is a representation of your signal strength. As this number approaches zero, your signal strength increases (so, –20 is better than –50). Experiment by moving your Mac, your wireless router, or both to see how high you can get this number.
You might also consider installing additional routers in your home or office to extend the reach of your Wi-Fi network. These days, mesh or hub-and-spoke wireless routers are all the rage, because they let you extend your Wi-Fi network easily and without wires; just add another router in another room if you need more range. My personal favorite in this category is the Orbi by NETGEAR. Since I installed a pair of these in my house, my Wi-Fi has been flawless—fast and seamless everywhere, with no fuss and no configuration hassles.
Interference
If you’re using the 5 GHz band with 802.11ac or 802.11n, you’re relatively unlikely to encounter interference from other devices. But with the 2.4 GHz band of N, or with B or G, you might see interference from:
Microwave ovens
Bluetooth devices
Other nearby 802.11 wireless networks
Cordless phones
Baby monitors
Other electronic equipment
What you should do: If you’re using such devices and can stop, or move them, do! Otherwise, tracking down sources of interference can be quite tricky, especially since they could be used by neighbors or random passersby. If you can’t move to an all–5 GHz wireless AC or N network, once again check out Glenn Fleishman’s Take Control of Wi-Fi Networking and Security, which offers practical suggestions for solving various Wi-Fi problems.
Check Your Wired Ethernet Connection
Whether or not you use Wi-Fi to connect your Mac to the internet, your home or office network is bound to use physical Ethernet cables somewhere. For example, you may have a DSL or cable modem that provides your broadband connection, and you may plug an AirPort base station, Apple TV, or other networked devices directly into it using an Ethernet cable. In more elaborate setups, you may have a whole series of gateways, routers, switches, hubs, computers, printers, and other doohickeys strung together with cables.
Although it’s generally true that wired connections are both faster and more secure than wireless connections, I want to be sure you’re aware of two key facts:
Ethernet comes in multiple speeds. Years ago, 10-megabit Ethernet was the standard, and then came 100-megabit and, still later, gigabit Ethernet. The iMac Pro is the first Apple device to include 10-gigabit Ethernet, and 100-gigabit Ethernet also exists. Many products have Ethernet ports that support two or more speeds—for example, a 10/100-megabit port supports both 10-megabit and 100-megabit Ethernet.
Bigger numbers mean higher bandwidth and faster throughput. But any connection between two devices is only as fast as the slowest link in that chain. For example, if you have a Mac with a gigabit Ethernet port but it’s connected to an older AirPort Extreme that has only 10/100-megabit ports, you’ll have a maximum of 100-megabit bandwidth. The moral of the story is: to get the fastest possible network performance, make sure all your devices—especially routers and switches—support gigabit or faster Ethernet.
Hubs are slower than switches and routers. When you run out of Ethernet ports, you can use any of several different types of devices to expand your network. Hubs are the cheapest by far but also the slowest, because a hub divides the available bandwidth equally among all its ports, while a switch or router makes the full supported bandwidth available simultaneously to all connected devices. These days, hubs are somewhat of an anachronism; you can still buy them, but most hubs you can find support only 10-megabit Ethernet (A few support 100-megabit Ethernet, but I’ve never seen such a creature as a gigabit Ethernet hub.) So look for a switch or router—and if you’re still using an old hub on your network, replace it with a gigabit Ethernet switch (they’re cheap).
Cables matter. Recently my ISP upgraded the speed of my broadband connection, and the computers in my home that use Wi-Fi immediately benefitted from the faster speed. But oddly, one of my Macs, which was connected to my cable modem’s gigabit Ethernet port with an Ethernet cable, was still poking along at slower speeds. I puzzled over this for a long time until it finally hit me: I was using an old, Category 5 (Cat-5) Ethernet cable for that connection, and those cables support up to 100 Mbps—but my broadband connection was now faster than that! So I swapped it out for a Category 6 (Cat-6) cable and the throughput shot way up. (I could also have used a Cat-5e cable.)
How can you tell if you have a Cat-5, Cat-5e, or Cat-6 cable? Look at the very tiny, very faint type that usually runs the entire length of the cable itself.
Use a Faster DNS Provider
Virtually any time an app on your Mac does anything on the internet—checking your email, loading a webpage, updating software, using Apple Music in iTunes, and so on—it must look up the IP address of the server it wants to communicate with. To do this, it uses the Domain Name System (DNS): it queries a device called a domain name server (or DNS server), which keeps records of which domain names (for example, takecontrolbooks.com) correspond to which numeric addresses (for example, 23.239.5.10). If the first DNS server your Mac asks doesn’t know the address, that server queries another, and so on up a hierarchical chain leading to a small number of authoritative servers for an entire top-level domain (such as .net or .com).
This system is fairly well known, but many people don’t realize that:
A seemingly simple activity such as loading a webpage could involve a handful, or even dozens, of DNS lookups.
DNS lookups take time, and must happen before any data can be transferred between your Mac and the server. So, the more DNS lookups that must take place, and the longer each one takes, the longer you must wait for the connection to become active.
Some DNS servers are much faster than others.
You’re not stuck with the DNS servers your ISP tells you to use; you have complete freedom to choose!
Every ISP provides DNS servers. Your ISP may give you addresses to enter manually when setting up your Mac and other devices, or may use a dynamic method, such as DHCP, to automatically tell your Mac which DNS servers to use. Either way, you can override this choice if your ISP’s DNS servers don’t perform as well as you’d like.
I know what you’re thinking, because I’ve trained you well: Shouldn’t there be a way to test this and find out for sure how fast my DNS servers are—and whether there might be an alternative?
Yes, there should be, and there used to be; now there is, but only sort of. You can download a free DNS benchmarking utility called namebench (Figure 11) that, within minutes, can tell you which DNS server is the fastest for your computer and your network, including the DNS server you’re using right now and various (free) regional and national services. All you have to do is click Start and wait for the results.
Unfortunately, at the end of its tests, when it’s supposed to display extensive results in a browser window, nothing happens for me—at least, not in High Sierra or later. Previously, it opened a browser window to display all the details, but when I retested it just now, the only thing it showed me after running a test was a subtle message at the bottom of the window indicating which DNS of the tested DNS servers happened to be the fastest in that test. That’s nice, but it doesn’t give me any actual speeds, show me how dozens of other DNS servers compare, or provide any of the other details it once did. And small wonder, given that the app hasn’t been updated since 2011; it has apparently been abandoned, and unfortunately I know of no good replacements. So, try if you like, but fair warning: it may not work as advertised.
In any case, if you want to use namebench’s recommendation—or just try a different DNS server to see what happens—do this:
Go to System Preferences > Network.
Select a network adapter (for example, Wi-Fi or Ethernet) in the list on the left, click Advanced, and then click DNS.
In the column on the left, click the plus
icon and type in an IP address. Repeat to add more name servers.Click OK.
Repeat for any additional network adapters you use.
Close System Preferences.
That’s it; you’re now using the new, faster DNS servers(s).
Test Your Broadband Service
The final element of network speed I want to address in this chapter is your broadband connection to the internet. I suggest that you consider these questions:
Is your current broadband service fast enough?
If not, might it be worthwhile to upgrade to a faster service—or even switch providers?
Depending on where you live and your budget, you may have anywhere from zero to dozens of choices for a broadband provider. Most people who live in urban areas can choose from at least two providers (perhaps DSL from one and cable internet access from another), and often can choose more than one tier of service from a provider. So there’s a good chance it will pay to look carefully at the numbers and see if you have a better option. But even if you’re unfortunate enough not to have any practical choice other than your current plan, you can find out how close your current provider comes to the service level they claim to offer—and if it’s substandard, you may be able to work with them to improve it.
So, we’re going to test your broadband speed—but first I want to make two disclaimers:
Broadband speed tests are, by nature, highly variable. You’ll get different results depending on the type of test you run, the location of the test server to which you connect, the time of day, and other factors. I suggest running several different tests at different times of day and averaging your results to get a more accurate picture of your typical speed.
Your results will always be slower than your broadband provider’s advertised maximum speeds, and that’s all right. Your ISP tells you the maximum bandwidth they provide with a given service, but your actual throughput will be slower, because That’s Just How Things Are. The speed may decrease further depending on how far you are from the provider’s switching equipment, how many other people are currently using the service, the weather (really, I’ve seen correlations between wet weather and slow DSL speeds), and other factors. So don’t worry if your provider claims “up to 10 Mbps” and you’re getting 6. On the other hand, do worry if they claim “up to 100 Mbps” and you’re getting 2. Your numbers will be lower, but they shouldn’t be massively out of proportion to the claims.
With those details out of the way, it’s time to find a broadband speed test. I just did a Google search for “broadband speed test,” and it returned over 900,000 results. So there are lots to choose from. Here are a few you might consider (in order of my personal preference):
Fast by Netflix (download speeds only)
After picking a test, follow these steps:
Restart your Mac.
To the extent possible, make sure no other devices on your network are actively accessing the internet right now—backing up files, checking email, downloading software updates, and so on.
Launch only your web browser—don’t run any other apps while the test is running—and make sure your browser has no other windows or tabs open.
Visit the website for the speed test you chose and run the test—usually a matter of clicking a single button (although Fast runs automatically). If you have the option to choose a test server location, choose the one closest to you.
Make a note of your results (which may include very different numbers for download and upload speeds), and then repeat with a few other tests and/or locations.
If the numbers seem reasonable to you, be happy and go about your business. If you’re unhappy with the results:
Try unplugging your DSL or cable modem, waiting a minute or two, and plugging it back in. (Do the same thing with your Wi-Fi router, if it’s separate from your DSL or cable modem.) When it comes back to life, run the test again. Sometimes a simple restart is all it needs.
Wait a few hours and try the test again. If you’re testing during peak hours, when lots of other people are using the network heavily, your results may be slower than usual. With the rise of video streaming, evening hours are often the slowest, as people start watching Netflix, Hulu, or whatever after dinner.
Talk to your broadband provider. There could be a technical glitch on their end, or a defect in your internet gateway or home wiring, that can be remedied to boost your speed.
If you’ve tried all the tips above and are still unhappy, politely express that unhappiness to your provider; be sure to include your test results as evidence that you’re not getting your money’s worth. They may trot out a line like, “We only claim you’ll get up to X Mbps, and we don’t offer any guarantees.” And that may, in fact, be true. But it never hurts to push back a bit; they may be willing to take steps to improve your service if they think they might lose your business.
If your provider can’t, or won’t, help out, start investigating their competitors (if any). DSLReports, for one, has ISP reviews that users have posted along with their own speed test results. But bear in mind that your experience may differ from someone else’s (due to your exact location and many other factors), so look for results that have been collected from many different people before drawing conclusions.