Improve responsiveness under load

The Advisor shows these steps when your responsiveness under load (Load RPM) is low: your connection is fast when it’s quiet, but slows down a lot while something else uploads or downloads. You notice it as a video call that freezes while a backup runs, or a game that lags while someone streams.

Why it happens

When a large transfer fills your connection, your router (or your ISP’s equipment) holds the extra data in a queue. Every other packet — the next frame of your call, a click in a game, a web page — waits in that same queue behind it. The queue is often much larger than it needs to be, so the wait grows to hundreds of milliseconds. This is called bufferbloat.

On Wi-Fi, the Wi-Fi link can also hold data in a queue while it is busy. This occurs mostly when other networks use the same channel.

PeakHour measures this with its speed test, which uses Apple’s networkQuality tool. The test fills your connection and counts how many round trips complete in a minute while it’s full. That count is the RPM (round trips per minute). A high RPM means the connection stays responsive under load; a low RPM means the queue grows.

The two steps

The Advisor gives the steps in this order:

1. Test over a cable. Run the Speed Test over a cable at the router to rule out the Wi-Fi. The Advisor gives this step only when your Mac is on Wi-Fi.
2. Turn on SQM. Turn on Smart Queue Management (also called SQM or QoS) on your router. This step links to this page.

When your Mac uses a cable, the Advisor gives only the SQM step. Go straight to Step 2.

Step 1: Test over a cable

Do this step when your Mac is on Wi-Fi. It shows whether the Wi-Fi or the router causes the low value. You then change a router setting only when the router is the cause.

1. Connect your Mac to the router with an Ethernet cable.
2. Run the speed test again. Click Run Speed Test on the Advisor’s Speed Test page, or use Settings → Dashboard → Speed Test → Run Now.
3. Look at the Responsiveness figures of the test.

Then read the result:

• The responsiveness is good over the cable (500 RPM or more). The Wi-Fi causes the low value. See Fix the Wi-Fi.
• The responsiveness stays low over the cable. The queue at your router causes the low value. Do Step 2.

Fix the Wi-Fi

• Move closer to the router or the access point.
• Use the 5 GHz or 6 GHz band. These bands are faster and less crowded than 2.4 GHz, but they reach less far through walls.
• Change the Wi-Fi channel on the router. Pick a channel that other networks use less. The This Mac card on the dashboard shows the channel and the band that your Mac uses.

For more steps, see Improve a weak Wi-Fi signal.

Step 2: Turn on Smart Queue Management

Smart Queue Management (SQM) keeps the queue short. The router sends data a little below your connection’s top speed, so the queue stays in the router, where the router can manage it. It then lets short, interactive traffic go ahead of large transfers. Routers call this SQM, Smart Queues, Adaptive QoS, Dynamic QoS or fq_codel / CAKE.

SQM usually costs a little top speed (often 5–10%) in exchange for a big gain in responsiveness.

Before you start

• Run a speed test without SQM, and note your download and upload speeds. Most routers ask for these numbers.
• Turn on SQM on the router that connects to your ISP. If your ISP’s modem is also a router, use the setting on whichever device does the routing.

Router steps

Menu names change between models and firmware versions. Look for the names above if the steps don’t match your screen exactly.

Ubiquiti UniFi

1. Open UniFi Network, then go to Settings → Internet.
2. Select your WAN connection.
3. Turn on Smart Queues, and enter your download and upload speeds.

eero

1. Open the eero app, then tap Settings → Network settings.
2. Turn on Optimize for Conferencing and Gaming. (eero calls its SQM by this name.)

ASUS

1. Log in to the router (often at router.asus.com).
2. Go to Adaptive QoS → QoS, and turn on Enable QoS.
3. If your firmware offers a QoS type, choose Adaptive QoS or (on Asuswrt-Merlin) fq_codel / CAKE, and enter your speeds.

Netgear Nighthawk

1. Log in at routerlogin.net.
2. Go to Advanced → Setup → QoS Setup.
3. Turn on Dynamic QoS, and run its speed test when it asks.

OpenWrt

1. Install the luci-app-sqm package (System → Software).
2. Go to Network → SQM QoS, choose your WAN interface, and enter about 90% of your measured speeds.
3. Under Queue Discipline, choose cake with piece_of_cake.qos.

pfSense and OPNsense

Set up Limiters with the FQ_CoDel queue for download and upload, at about 90% of your measured speeds, and apply them to your WAN traffic. The documentation for your firewall has the full steps.

If your router has no SQM

Many ISP-supplied routers don’t offer SQM. You can put your own router behind the ISP’s equipment and turn on SQM there, or ask your ISP whether they offer a router with it.

Check the result

In PeakHour, run a new speed test (Run Speed Test on the Advisor’s Speed Test page, or Settings → Dashboard → Speed Test → Run Now). Your Load RPM should rise, and the Advisor stops showing these steps once your responsiveness is good. If the RPM didn’t change, check that SQM is on for both directions, and try lower speed values.