imacssd
I recently upgraded my HDD to a SSD. Before upgrading I never checked fan speed.
Now, after my upgrade the fan spins at 1400 rpm on idle.
Is this normal? I thought it would be quiet like on a MacBook Pro, with the fan turning on after it reaches a certain temperature. However, it seems to me the fan is now on sooner and because of this my iMac is noisier than before.
Can someone who has original hdd check fan speed and temperature and post it here?
As you have seen, all Apple products actually run even when you power them off. On iOS, the battery keeps time and on Macs, the SMC is responsible for knowing when the power button is pressed and if the Mac should start itself up due to a scheduled wake or power on being saved in the NVRAM.
If you called for service, Apple would likely focus on several things:
Assuming you can reproduce this at will (it happens every time), you would probably take steps to reset the SMC to ensure it's getting proper readings from the temperature sensors.
If after spending the 10 minutes it would take to read through each and every step (I feel it's important to perform the steps in order - even if they seem unrelated or unnecessary), I would expect them to want to run diagnostics to physically open the Mac to check the sensors and wiring. Your symptoms sure sounds like the SMC either is stuck in some loop and not reading the temp sensors. Failure to control the fans properly could also be a hardware issue where the SMC is receiving a signal where the correct action is to keep the fans not only spinning, but spinning at an elevated level.
I am a firm believer in avoiding software "hacks" to fix hardware issues. To fix this problem, you need the sensor. Unfortunately, as you have found out, your SSD doesn't support this connection.
However, OWC makes an digital inline temperature sensor. Basically, it goes between the SATA power cable and the SATA power connector of your HDD/SSD. The temp sensor goes on your drive.
The best part about this is that it's a "once-and-done" solution meaning future OS upgrades won't be susceptible to software incompatibility problems like you are experiencing now.
C|Net did an article on this exact problem and a review of this solution.
Best Answer
A fan speed of 1400RPM really is nothing to worry about. And your model iMac does not require an external thermal sensor for an ssd upgrade, so that shouldn't be an issue for you.
My first step would be to try resetting your System Management Controller. To do this:
Software option
You can also try installing SSD Fan Control to see if that resolves your issue. However, I would only do that if the SMC reset does not resolve your issue.