Windows 10 extremely slow on iMac 2017

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Windows 10 extremely slow on iMac 2017

Hello, I have recently installed Windows 10 on my 2017 iMac using Boot Camp. The installation went fine. After I booted in Windows 10, I installed all the drivers using Boot Camp driver utility and even installed additional AMD GPU driver for my RX570. I have checked the device manager, computer has recognized everything and there are no errors. The problem is that Windows 10 works extremely slow for some reason. Apps open and close super slow, booting up takes about 3 minutes and the overall performance is terrible. I have also checked Task Manager to see if there is any problem but there wasn't. But I have noticed that when I open and close apps and use them the CPU usage never goes any higher than ~40%. There is workload but the CPU just doesn't want to use it's full potential. However, when I boot back to macOS the performance seems to be as usual. I know that I have HDD instead of SSD but my 2012 MacBook Pro also has an HDD but it is at least 3 times faster than my new iMac when using Windows. Maybe the problem is Windows 10 itself, my MacBook Pro 2012 is running Windows 7 and I'm not a very big fan of Windows 10 bacause of all the bloatware etc. Can someone please help me with this?

iMac Line (2012 and Later)

Posted on Aug 31, 2019 9:04 PM

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Answer 1

Loner T

Level 9

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Sep 7, 2019 5:35 PM in response to kristianzz.c

Can you check if Windows in Safe Mode works? If yes, how long does it take to boot into Safe Mode?

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Answer 2

Loner T

Level 9

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Sep 2, 2019 8:09 AM in response to kristianzz.c

Can you check the negotiated SATA link speed on the HDD controller?

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Answer 3

Loner T

Level 9

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Aug 31, 2019 9:09 PM in response to kristianzz.c

From both 2012 and 2017 Macs, in System Report, post the details of the HDD. It is much simpler to explain, once that information is visible.

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Answer 4

Loner T

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Sep 1, 2019 6:59 AM in response to kristianzz.c

This looks to be a normal APFS Fusion drive. As a test, can you run a SMC and NVRAM Reset and check the performance?

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Answer 5

Loner T

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Sep 7, 2019 11:12 AM in response to kristianzz.c

Glad it is 6Gbps. This also means the hardware is fine. Do you have BitLocker enabled? Secure Boot can also cause delays.

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Answer 6

Loner T

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Sep 6, 2019 8:58 AM in response to kristianzz.c

Take a look at https://superuser.com/questions/633839/how-can-i-determine-the-sata-controller-version-on-windows .

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Answer 7

kristianzz.c Author

Level 1

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Sep 1, 2019 6:50 AM in response to Loner T

I can only post my iMac's system report because yesterday I swapped my MacBook's HDD for an SSD. I do know that I have a fusion drive (SSD+HDD) in my iMac but it is still very odd that my iMac was slower than my MacBook because my MacBook had a 5400 rpm HDD and my iMac has 7200 rpm HDD, theoretically it should be faster or at least the same (I'am talking about Windows not macOS because I do know that macOS is running on the SSD part of the fusion drive).

[Image Edited by Moderator to Remove Personal Information]

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Answer 8

Loner T

Level 9

59,606 points

Sep 1, 2019 6:52 AM in response to kristianzz.c

This is from a 2014 iMac. I do not run into any issues similar to yours. I am on macOS Sierra, with a CoreStorage Fusion drive, instead of an APFS one.

Also, I do not have OSXRESERVED, which has no performance implications.

Once you boot into Windows, you should get reasonable performance.

[Image Edited by Moderator to Remove Personal Information]

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Answer 9

kristianzz.c Author

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Sep 1, 2019 6:32 AM in response to Loner T

I don't think that this has something to do with formats. I had to rebuild one time the whole fusion drive because it was split in half. Mac didn't recognize SSD and HDD as one. I rebuilt them back into a fusion drive with terminal and formatted it to APFS in disk utility. But even before this the performance was terrible in Windows. Are you running Windows 7 or 8 or 10?

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Answer 10

Loner T

Level 9

59,606 points

Sep 1, 2019 6:40 AM in response to kristianzz.c

kristianzz.c wrote:

I rebuilt them back into a fusion drive with terminal and formatted it to APFS in disk utility. But even before this the performance was terrible in Windows.

Can you post the output of

diskutil apfs list