Hello everyone,
I have a wonderful 27″ mid-2011 iMac. A few years ago I installed a new 1TB Hard Drive (spinning SATA). When I booted up the new install, the iMac fans went crazy. Very loud and going full speed. This is why:
The Hard Drive that Apple uses from the factory has a proprietary controller on it for reporting the drive temperatures to the motherboard. My new drive had no temperature sensor on it, so my iMac motherboard didn’t know what the HD temperature was. It therefore ran the fan speed at 100% all the time.
I certainly didn’t want to open the thing back up so I went with a software solution. I choose smcFanControl and I was fairly satisfied but I did notice that the back of the iMac still got very hot to the touch. I also had to be constantly adjusting the smcFanControl settings.
About two months ago I decided to go with an SSD drive and I chose the Crucial MX500 SSD. I did not want to control the fans via a software solution so I “bit the bullet” and bought the $39.00 OWC In-Line Digital Thermal Sensor Cable. I did not want to pay the $39.00 but I wanted to do the upgrade the right way and I knew that a hardware solution to the fan problem was the right way to go.
So, off comes the glass (you really don’t need suction cups), and after eight screws out comes the screen. Now you have the four cables to disconnect:
- Vertical Sync Cable
- Backlight Power Cable
- Display Port Cable (not too difficult to disconnect but quite difficult to reattach).
- Display Power Cable
OWC has a great video here. I bent the Display Port Cable initially and had to order another one from ebay. Finally I updated to macOS High Sierra (can’t go any higher on the mid-2011), and the machine ran like a clock. No fan noise and the new SSD was much more responsive. At some point I’m going to add 4 more GB of memory and I figure I’ll be able to use this machine for a few more years.
The upgrade was fun. Don’t be afraid to give it a try. Just follow the OWC video and you’ll do well.
Best wishes and Happy New Year!
Randy The Tech Professor
12:35 pm on August 24th, 2019 1
Randy, I want my fans to come on at full speed to blow the dust out. Is there a way I can make them come on HIGH. It was getting hot to the touch and I blew the top slit with compressed air, also in the back. middle in the round hole. The fans used to come on at full speed occasionally to blow dust out but they haven’t for two years. I don’t want to take it to a computer tech. Not very good ones here in Central FL and I don’t want to take back off. Thanks.
12:38 pm on August 24th, 2019 2
Randy, I forgot to say I use a 2011 imac still on Snow Leopard and loving it but I want to make my fans come on at 100% to blow the dust out.
3:25 pm on September 9th, 2019 3
Hello Michael,
Download and run Macs Fan Control (https://www.crystalidea.com/macs-fan-control). Set the fan speed to 100% (but not for too long).
This will blow out some dust and then you can set the fan speed at a more normal speed to keep your iMac cool.
Love the 2011 iMac!! So upgradable and I still love the optical drive. I have 8GB of RAM and a 500GB SSD drive in mine.
Best wishes,
Randy
9:35 am on April 27th, 2020 4
Has anyone else had the problem with SSD Fan Control or Macs Fan Control whereby the daemon freezes the system (keyboard and mouse have no effect, and spinning beachball of death spins until power cycle). It took me a long time to isolate, but manually starting the daemon consistently froze the system.
7:06 am on October 16th, 2020 5
Just encountered the same problem as Hugh. Discovered that when booted from a USB drive, starting the SSD Fan Control daemon causes the SSD to entirely disappear from the System Information – hence the freeze when booted from the SSD itself.
2:02 pm on November 1st, 2020 6
Chris Upton: did the proposed solution fix the problem?
8:03 pm on July 9th, 2021 7
I am using Mac Fan Control for several years on an iMac 21 mid 2011 when the HDD was replaced by an SDD.
Since a few weeks ago, fans speed are always faster and makes noise.
I went to the control and realize the slowest speed for all fans have change which explain the noise.
The HDD fan speed use to have a range from 1200 rpm to 5500 a few weeks ago.
It is now form 3700 to 6300.
I don’t know what has changed, I boutgh the Mac Fan Control Pro version thinking the preset would allow me to reduce the speed to 1200 has before, but no, still min of 3700 even with the Pro version.
So Something has changed.
Previously, FAN speed were
ODD 700 to 4400
HDD 1200 to 5500
CPU 1200 to 3300
Now
ODD 2675 to 4350
HDD 3700 to 6300
CPU 2600 to 2600 ?? weird
Any one else seeing this ?
Thanks