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A couple of months back my MacBook Air’s SSD, which had given indicators of failure, was replaced with the same type, APPLE SSD SD0128F.

Very soon after it was replaced I noticed that the fan was coming on more often and running at a higher speed than it used to. My usage (and other factors were just about the same; no change there.

Within a month my usage actually decreased yet the fan would stay, and stays, almost always on and at high speed. In addition, the laptop was/is heating up from the upper-left (strip above the Esc) much more than it ever used to.

The Activity Monitor (which I have long had in my dock) icon view and its detailed view, especially of CPU usage, reflects and confirms my feeling that soon after SSD replacement my usage indeed stayed the same and that soon thereafter it actually decreased.

So why would replacing an SSD have the direct result of the laptop heating up?

agarza
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kds-kds
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    First guess would be that you either changed the airflow within the Mac during the replacement, or broke something (e.g. the temperature sensor). Did you reopen the MBA to check for issues? – nohillside Nov 13 '23 at 16:20
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    Did you reset the SMC ? The SMC manages thermal and battery management. the SMC can effect performance, and also cause bugs like fans that run constantly even when CPU usage isn't high. – Ruskes Nov 13 '23 at 16:55
  • I didn't do the replacement so I don't know but I shall ask the technician and find out. Will get back to you both. Thanks very much. – kds-kds Nov 15 '23 at 09:10

2 Answers2

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The simple explanation is the system is running hotter.

We are not going to be in a good place to guess what you can see and measure with your eyes.

  1. Get some measurements on the case when the system is cool and when it's running and when the fans are hot. Infrared surface measurement tools are about $15 and very accurate when you use the same device in the same position and measure the same object at different times. The calibration of absolute temp may be off, but the relative accuracy is typically very high.
  2. Open and inspect that the blower is free and you didn't bump the heat pipes for your model. Reseating them with thermal compound and ensuring the blower operates (listen in a quiet room when it spins up) to be sure active cooling and passive cooling is working.
  3. Get an add on program (iStat menus) after you've done both of the above - they can drive temp even higher based on how often they are checking and graphing - but if you set them to update once every 5 minutes and not draw graphs all the time you should be able to get accurate blower speeds and internal temps from the existing sensors.

You'll want to gather stats over several days of a week to ensure spotlight and other intermittent CPU loads even out. Good use of Activity Monitor to profile and spot check things.

bmike
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Since you changed hardware the SMC might be confused.

The SMC manages thermal and battery management. the SMC can effect performance, and also cause bugs like fans that run constantly even when CPU usage isn't high.

Look up how to reset SMC on your Mac.

Since the CPU is by far the biggest heat generator, while the SSD is not, that why you can have external SSD without cooling fan.

How to check the CPU temperature without adding new app's.

Open Finder>Applications>Utility and click on the Terminal and enter

sudo powermetrics --samplers smc |grep -i "CPU die temperature"

Enter your system password (it wont show what you are typing) so be precise.

Sit back and observe (it will continuously display the result)

cpu

Ruskes
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    Thanks very much for this valuable tip. Here are the results:

    CPU die temperature: 85.02 C CPU die temperature: 84.23 C CPU die temperature: 83.45 C CPU die temperature: 82.82 C CPU die temperature: 83.12 C CPU die temperature: 82.50 C CPU die temperature: 81.94 C CPU die temperature: 81.43 C CPU die temperature: 81.52 C CPU die temperature: 80.94 C CPU die temperature: 80.95 C CPU die temperature: 82.34 C CPU die temperature: 86.52 C

    Did a quick search and found that this is definitely on the hot side.

     – kds-kds Nov 15 '23 at 09:14