sphinxy
Newbie Boot Camper
Posts: 5
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Post by sphinxy on Apr 30, 2020 0:24:29 GMT
Hi all, like many of you I've been frustrated by the thermal throttling of my iMac 5K (Late 2015, M395X) in games. I just finished writing up a workaround I found using smcFanControl under macOS to force the computer to run its fans above Apple's firmware limits, at the cost of noise. I've found that this almost completely eliminates throttling and allows the GPU to run at nearly full speed without underclocking or stuttering. It works best under Windows with the latest drivers, but performance gains of up to 40% can also be seen in macOS as well. I think it'll be very useful to many of you in this community:
I suspect that this will also ease throttling on other Mac models as well. Feel free to post your results here if this helped you.
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Post by moisterrific on May 4, 2020 5:40:09 GMT
I just use MacsFanControl in bootcamp and ramp the fans up to full blast at all times. Don’t mind the noise since I almost always use headphones. Easier to replace fans if they break down than the CPU or GPU since those are soldered onto the motherboard.
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sphinxy
Newbie Boot Camper
Posts: 5
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Post by sphinxy on May 7, 2020 5:01:23 GMT
I just use MacsFanControl in bootcamp and ramp the fans up to full blast at all times. This helps, but if you read my post, you'll see that in my testing "full blast" as the firmware reports it actually isn't all the fan is capable of, but rather a speed determined by Apple to be the "best" balance of noise and performance. Macs Fan Control simply reads this "balanced" maximum speed from firmware and writes it in as the active target speed. This ignores what the hardware is actually capable of though.
smcFanControl lets you write values directly to the SMC, which controls the fan, and you can use in order to run it at 100% of the speed it's actually capable of (i.e. bypassing the stock limit and pulse-width-modulation-based speed control, thereby feeding the fan a full 12V of power) and benefiting with performance numbers double-digits above what you would get with the firmware's default reported "maximum" fan speed and Macs Fan Control. I didn't include performance/thermal throttling numbers with this stock "balanced maximum" fan speed in my post, but they represented a middle ground between the numbers you see for the "stock automatic" fan behaviour and with the fan's actual maximum speed as set with smcFanControl's command line utility, which I did include data for in my post. |
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Post by gamerpro on May 19, 2020 19:54:54 GMT
Hi all, like many of you I've been frustrated by the thermal throttling of my iMac 5K (Late 2015, M395X) in games. I just finished writing up a workaround I found using smcFanControl under macOS to force the computer to run its fans above Apple's firmware limits, at the cost of noise. I've found that this almost completely eliminates throttling and allows the GPU to run at nearly full speed without underclocking or stuttering. It works best under Windows with the latest drivers, but performance gains of up to 40% can also be seen in macOS as well. I think it'll be very useful to many of you in this community:
I suspect that this will also ease throttling on other Mac models as well. Feel free to post your results here if this helped you.
How do you do this I was just ready to give up gaming on iMac 5k cause it keeps throttling even with fans maxed with Mac fan control? |
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ole
Newbie Boot Camper
Posts: 3
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Post by ole on May 20, 2020 14:10:43 GMT
Actually you could also download prefs editor and change the maximal setting for your computer in the plist of SMC control.
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Post by FlyingAdmiral2187 on May 21, 2020 6:55:24 GMT
Hi all, like many of you I've been frustrated by the thermal throttling of my iMac 5K (Late 2015, M395X) in games. I just finished writing up a workaround I found using smcFanControl under macOS to force the computer to run its fans above Apple's firmware limits, at the cost of noise. I've found that this almost completely eliminates throttling and allows the GPU to run at nearly full speed without underclocking or stuttering. It works best under Windows with the latest drivers, but performance gains of up to 40% can also be seen in macOS as well. I think it'll be very useful to many of you in this community:
I suspect that this will also ease throttling on other Mac models as well. Feel free to post your results here if this helped you.
Hi sphinxy ! THanks for the article.
Can you also please help me and tell me how to do this procedure on the iMac Pro with the T2 Security chip. Since the SMC Command seems not to work. Or maybe I am doing it wrong. I always get Error: SMCWriteKey() = e00002bc even with sudo.
I also have any security measue turned off that can be turned off.
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sphinxy
Newbie Boot Camper
Posts: 5
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Post by sphinxy on May 21, 2020 23:33:50 GMT
Actually you could also download prefs editor and change the maximal setting for your computer in the plist of SMC control. Thank you so much for this suggestion, it is way easier than modifying smcFanControl from source code or using the command line version!  I have updated the article with a new how-to section utilizing Prefs Editor, to streamline the process for anyone who wants to try on their own. How do you do this I was just ready to give up gaming on iMac 5k cause it keeps throttling even with fans maxed with Mac fan control? As I mentioned in the article, Macs Fan Control enforces the default maximum fan speed no matter what, and takes control over the fan speed as soon as it's launched. You need to disable the option to have Macs Fan Control run at boot, then follow the instructions in the new how-to section to use smcFanControl to set your fan speed. Hi sphinxy ! THanks for the article. Can you also please help me and tell me how to do this procedure on the iMac Pro with the T2 Security chip. Since the SMC Command seems not to work. Or maybe I am doing it wrong. I always get Error: SMCWriteKey() = e00002bc even with sudo.
I also have any security measue turned off that can be turned off.
If you find or figure out a solution that works, please let me know — I'd be happy to update the article with your findings!
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Post by gamerpro on May 29, 2020 20:54:36 GMT
it worked mine maxed at 4000 rpm
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ianj
Newbie Boot Camper
Posts: 1
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Post by ianj on Jun 4, 2020 9:52:32 GMT
Thank you so much! This method is by far the only method that actually works. The fan's speed goes from 5000 to 7000, and my MacBook Pro 2018 15-inch's temperature is now constantly below 72 degrees. People with throttle issues should definitely try this one.
Like many others, my Mac's GPU core clock will drop down to around 300 MHz minutes after the temperature gets 80+ degree, and with fluctuate between 300-500ish MHz even if the temperature goes down to around 74 degrees. The recent macOS's update may have messed up something causing this odd behavior.
Sadly preventing temperature from going above 80 may the only but temporally fix. This fix is a little bit annoying, because you have to login to macOS every time before using Windows. Hopefully Apple will eventually fix this.
P.S. These are the methods I'm using now: Max fan speed(smcFanControl) + Turbo disabled and CPU power limited to 25W(QuickCPU) + GPU Clock set to 640 MHz(MSI Afterburner) + 2020 Jan driver
(CPU limitations may be unnecessary, but in my case the GPU Clock MUST be tuned down since the temperature will always go beyond 80 when set to default 1004 MHz)
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Post by nickaroot on Jun 9, 2020 3:16:24 GMT
Hey, T2 chip guys  I found the way to override speed limitation by using Macs Fan Control and Cheat Engine Steps: 1. Install Macs Fan Control (https://crystalidea.com/ru/macs-fan-control) 2. Install Cheat Engine (https://www.cheatengine.org/) 3. Start Macs Fan Control 4. Set constant value for Left Side - 4444 5. Set constant value for Right Side - 3333 NOTE: You can choose ANY value, we need it only for filtering in Cheat Engine 6. Start Cheat Engine 7. Attach to MacsFanControl.exe process (top left button, select MacsFanControl.exe, click "Attach debugger to process" button) 8. Scan for "4444" (Enter "4444" to "Value:" field, "First Scan" button click) 9. Select all found addresses (left panel) and copy items to the Address List (the red arrow button click) 10. Select all addresses on Address List (bottom panel) 11. Change value for selection to "6000" or any other value (right click on selection, "Change Record" - "Value" menu item click, change value to "6000", "OK" button click) NOTE: Left side override done, now we expect increased left fan speed (Macs Fan Control show actual overridden fan speed), you can change it back with Macs Fan Control interface. 12. Click "New Scan" button 13. Repeat 8-11 with "3333" search value to override the Right Side fan speed DISCLAIMER: You can damage your hardware, use it on your own risk |
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m10
Newbie Boot Camper
Posts: 8 
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Post by m10 on Jun 15, 2020 8:39:59 GMT
Will the fans run at max speed in Bootcamp as well after doing this ?
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Post by nickaroot on Jun 16, 2020 13:32:54 GMT
You can do it with Windows versions of Macs Fan Control and Cheat Engine
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Post by gamerpro on Jun 19, 2020 20:39:52 GMT
whatin the world is this magic radeon pro 570 suddenly 2.5x faster in skyrim se went from 40 fps to rock soild 60 fps now fast as gtx 1060 maybe 1070!
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sphinxy
Newbie Boot Camper
Posts: 5
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Post by sphinxy on Jun 20, 2020 0:02:55 GMT
Hey, T2 chip guys I found the way to override speed limitation by using Macs Fan Control and Cheat Engine - snip - That's exciting to see! I'd like to update my guide with your findings, but it looks like Cheat Engine bundles some adware/PUPs that make me hesitate on recommending it. If you can find another memory editor that works and doesn't bundle malware, I'd be happy to add your solution to my article. Will the fans run at max speed in Bootcamp as well after doing this ? Yes! As mentioned in my article, values set by smcFanControl persist across reboots (but not a complete shutdown). whatin the world is this magic radeon pro 570 suddenly 2.5x faster in skyrim se went from 40 fps to rock soild 60 fps now fast as gtx 1060 maybe 1070! No magic here, just helping you get your money's worth out of the hardware you paid for. Very glad to hear my guide was useful to you! Skyrim SE was actually the game that pushed me to try this workaround to begin with! |
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toast
Newbie Boot Camper
Posts: 1
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Post by toast on Jan 24, 2021 5:52:37 GMT
I know that this thread is rather old, but I have found a way to remove the fan speed limitations under Windows without memory editors, thus there is no risk running this configuration while playing online games.
Though I could not figure out how I could make the speeds scale dynamically based on CPU temperature, it can be scaled against the internal GPU's temperature, simply change "sensorControlMode" in FanControl.ini to 2. Scaling based on CPU probably requires changing "CPUkey". Fully shut down your Mac (with shut down, not restart) to reset fan speeds to default.
Note that I have only tried this on my 2017 5k iMac, which does not have a T2 chip, so your results may vary.
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