How to know what is causing a cursor lag on Mac?

Question

I want to know if there are ways to identify the cause of the delay and lags in cursor when I use the mouse and Magic Pad. Any tools or indicators on Mac to monitor to see the root causes?

I’m using Mac mini with a Logitech mouse and a Magic Pad, connecting to the Mac with unifying (wireless USB transmitter) and Bluetooth respectively.

I don’t think the CPU and the memory are the issue. According to the activity monitor, the CPU idle is usually at 80%, and the memory still not busy.

By the way, I feel the lag after upgrading to MacOS Mojave.

--Answer for my situation-- With some investigation, I found that the cause might be that I had a poor USB connector. According to the thread, some USB connectors disturb the network of Wifi 2.4GHz and Bluetooth devices. After removing the connector, I haven't experience the problem so far.

Solution 1

I have disabled the Handoff feature on my iOS device - and the lag has disappeared.

Solution 2

As the cause can be both hardware and software related, different measures have to be taken to examine the root cause of your cursor lag.

Hardware

Seeing as your issue affects several peripherals, it is less likely that they are defective. It is however recommended to try to connect them to a different computer to exclude this as a possible cause.

There does exist a problem with radio interference when using 2.4 GHz devices (Logitech Unifying Receiver / Bluetooth) along with a USB 3.x peripheral connected to the computer. This interference is known to cause significant lag in the mouse response. I would begin by investigating if this issue applies to you before moving on to other sources. Simply identify if any USB 3.x peripherals are connected. If so, disconnect them and consider if the cursor movement changes. The USB 3.x issue causes erratic behavior in the cursor which should then be gone.

Software

Look into conflicting applications. Disable all non-essential running applications - especially those directly affecting the cursor such as SmoothScroll, Scroll Reverser, Steelseries ExactMouse Tool, Steermouse, BetterTouchTool and so forth. Evaluate if the issue is resolved by disabling the applications. If this is the case, reactivate them one by one to find the exact culprit. The problem could be associated with two applications in conflict, as the Apple macOS APIs can respond differently when two apps use them simultaneously.

To further evaluate the cause of the issue one can use applications such as iStat Menus to look for usage spikes related to the lags. Further analyses will have to be done.

Solution 3

I had the same issues when moving the USB dongle to the other side of the Mac Book so that the Mac Book was in between the dongle and the mouse. As soon as I moved the dongle closer to the mouse and connected it into a docking station with nothing in between dongle and mouse, lag was gone.

Solution 4

I had these issues when I plugged in just the USB 3 cable to my recently acquired Mac Mini 2014 and had the cable across the unit, when I unplugged them or moved them to the side the jitter went away. even worse I had a dual dock next to the Mini and it destroyed the b-tree node on all the hard drives (x4) I put in there, so I couldn't mount them anywhere after that, moved the dock away and it's working fine so far.

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Comments

[MMB]

If I understand you correctly, you're using cursor lag to as a symptom to describe a slow computer. If that is correct, what version of the Mac Mini do you have? You can find the exact version on the third line of the "About This Mac" window below the Mojave version number. Also, how much RAM do you have?

[Alex]

would give multiple up votes if I could.

[theStud54]

I have BetterTouchTool and the MX Master 2s that I use with the unifying receiver and bluetooth (sometimes). I have noticed this lag and thought it was BetterTouchTool but I think you link to the USB 3 (My external hard drive) is actually the cause!! Thank you for the answer.

[Nerolite]

Good to hear that you found the issue! USB 3.x problems can be mitigated by creating some distance from the interfering device, or improve the shielding. This can be achieved by e.g. switching the external drive to USB ports on the other side, using an extension cable for the unifying receiver, or connect either the receiver or drive through a dock. Good luck!

[theStud54]

It’s been phantom and I’m now wondering if my dell ultra wife connected via DisplayPort to usb c could be a cause. Thoughts? I’m thinking of buying a new cable

[Nerolite]

I will assume that a plain USB C to DisplayPort cable is being used. In that case I doubt this is the culprit. One could attempt to verify this by intentionally keeping the cable and Unifying Receiver close to each other while attempting to use the mouse, to see if the issue can be recreated. You say the problem is phantom. Have you experienced the issue when no other USB 3.x devices have been attached?

[pmbaumgartner]

Thank you for sharing, this is the solution that worked for me. I have an iPad that was trying to connect to my work laptop which is on the same wifi.

[matan7890]

My docking station was close to the display port to USB C cable that was connected to the computer. As soon as I moved it a little back and rotated it to the direction of the cursor the lag disappeared. Thanks Nerolite!