Problems · Specific machines
Why does my MacBook Air M4 slow down during long tasks?
Because it is fanless, and fanless machines trade sustained speed for silence. Reviewers running ten consecutive Cinebench 2024 loops on the M4 Air logged a first score near 844 settling into the mid-600s, with occasional recoveries into the 700s: a taper to a sustainable level rather than a collapse.
That behaviour is the design working. What is worth investigating is a machine that feels slow outside sustained load, which on the M4 Air almost always points at memory pressure or storage rather than heat.
First, notice when it happens
The causes, ranked
1. The fanless taper, working as designed
most commonHow to confirm it
Sustained load, a warm body, no noise, and a decline that levels off rather than continuing downward.
The fix
Nothing to repair. The machine has found its sustainable level and will hold it, which is the behaviour Apple engineered for.
2. Memory pressure on the base configuration
most commonHow to confirm it
Stutter and beachballs during ordinary multitasking, not during long exports. Activity Monitor's memory pressure graph in yellow or red confirms it.
The fix
Reduce simultaneous applications and tabs. The memory is soldered, so this is the only lever on the machine you own, and the reason to specify more on the next one.
3. Insulation: soft surfaces, thick cases, closed lids
commonHow to confirm it
Slower on a bed or under a thick case than on a desk, because the body is the radiator and anything touching it is insulation.
The fix
Hard surface, and a stand rather than flat-and-closed when driving external displays.
4. A runaway process rather than a workload
commonHow to confirm it
Warm and slow with nothing heavy running. Sort Activity Monitor by CPU: a stuck helper, a sync client or a runaway browser tab is usually at the top.
The fix
Quit and restart the offending process. This is the most common cause of an Air that seems slow for no reason.
5. Sustained professional work on a consumer machine
occasionalHow to confirm it
Long renders, large compiles or hours of virtualisation, where the settled level rather than the peak sets your completion time.
The fix
A MacBook Pro's fan exists for exactly this. On the Air, plan around the settled figure rather than the headline one.
Measure it instead of guessing
Run the test and read where the curve levels off. On an M4 Air the settled level should sit meaningfully below the peak and then stay flat, which is the taper reviewers measured. A curve that keeps sliding, or one that starts low, is telling you about something other than the design.
What software cannot tell you here
- We cannot read Apple's temperature sensors, memory pressure or storage from a browser.
- We cannot tell a design taper from an insulated machine in one run; testing on a hard surface and comparing does that.
Asked, in people’s own words
- Does the M4 MacBook Air throttle?
- Yes. Across ten sustained Cinebench 2024 runs reviewers saw a first score near 844 settle into the mid-600s, with occasional bursts back into the 700s. The important detail is that it tapers to a sustainable level and holds there rather than falling away, which is what makes it liveable.
- Is the M4 Air fast enough for video editing?
- For 1080p and moderate 4K work with well-supported codecs, comfortably, because Apple's media engines do the heavy lifting and most editing is bursty. For long exports, multicam 4K and effects-heavy timelines, the settled level rather than the peak sets your times, and a machine with a fan finishes sooner.
- Should I buy the MacBook Air or the MacBook Pro?
- If your heaviest work finishes in seconds or a couple of minutes, the Air is the better machine: silent, lighter and cheaper for the same burst speed. If you regularly run loads for ten minutes or more, the Pro's fan is the entire reason it costs more, and it buys back exactly the performance the Air tapers away.