CPU permanenttly works on half of clock

Hello everyone!

I encountered with problem and I have absolutely no idea how to resolve it.

I have an iMac mid 2011 27" with core i5-2400 (3100MHz) radeon 6970-1gb HDD 1TB .


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My HDD had broken, so i decided to install SDD instead of it. So I replaced old hard disk and put ssd Crucial MX200 500Gb instead. I installed Mac OS 10.7 from scratch using embedded recovery system, and after what updated to 10.11.5.

Everything was fine until I decided pass some benchmarks. And all benchmarks show that cpu results only a half of expected. E.g Cinebench R15


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I tried to figure out what the problem and install Intel Power Gadget utility.

It reveals next - CPU frequency does not rise higher than 1600MHz even in 100% cpu load tasks. It freeze on 1.60GHz a not move even a bit. The line on the graph is absolutely flat!


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And there are no CPU overheat as all! Temperature not raises more than 50C degrees.

And GPU also work at ~20% of it power according to benchmarks (two times less points than ge-force 620m has).

I have no idea how to resolve this issue. Please share your experience in such cases

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1 Answer

Chosen Solution

First take it in to an ASP and have it tested for this free repair program: https://support.apple.com/en-us/HT203787

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Unfortunately we have not official Apple service in our country.

And there are no symptoms described at Video Card Replacement Program. Video works fine, without artefacts and any other distortions. And everything was OK until i replaced old hdd with ssd : (

It seams to me some power management issue occurred. But i thought Intel CPU throttle mechanism works independently of os x


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Vladyslav will be eternally grateful.
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