GPU/CPU working at 50%

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iMac Intel 27" EMC 2429

Model A1312 / Mid 2011 / 2.7 & 3.1 GHz Core i5 or 3.4 GHz Core i7 Processor, ID iMac12,2

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Predrag @predragns

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发帖于: 2018年5月15日

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GPU/CPU working at 50%

Hello,

I have old iMac Intel 27" EMC 2429, under OS X, tried many versions, my CPU is not turbo boosting at any time, it works at 1.6ghz, and my GPU is working at some 30% of speed it should work at.

On the other hand, under windows bootcamp my graphic card is working at 100% but CPU is still not turning turbo boost on and i get flat 1,6ghz.

I don't have screenshots on my home computer to show for but if anyone has any idea what can be the reason behind this it would help me.

p.s. i have noticed GPU flow (not right away) after graphic card replacement, sadly after 3 months of replacement guarantee have passed.

Ok @danj it seems we are on right track, it looks to me like they are tore off in my case too, what is my next move? :) do you know what exactly i need to buy to soldier on?

screenshots after fix

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Not enough info here to help.

Did you run diagnostics on the system? Also down load this app: TG Pro so you can monitor the systems thermal sensors and fan. Tell us the error from AHT and snap a screenshot of the full main window (you may need to expand it a bit to get all of the sensors visible) and paste it here for us to see. 在已经存在的问题里加入图片

You also spoke about replacing the GPU card what card is your system using now?

由 Dan 完成的 2018年5月15日

i get this error in AHT: 4sns/1/c0000008: TAOP--124

i have also purchased replacement sensors some time back, 2 of them and tried replacing it, tried both of them and problem is still there.

I have uploaded screenshot from TG Pro, my fans are going berserker since Macs Fan Control won't start atm...

I have just reinstalled Macs fan control and took snapshot from it's sensor readings.

also i have just uploaded images from cinebench from both mac osx and windows 10 for reference.

ill try to put longer AHT now to do it's magic.

由 Predrag 完成的 2018年5月31日

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Dan @danj

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Can you give us some background here on what you’ve done with the system. Like did you replace the HD, add a second drive or remove the logic board?

@predragns OK I think I know what happened as it happened to me! In the process of removing one of the sensor cables (AMB TEMP) I damaged one of the coils. Here’s the area you’ll need to inspect:

Is either L5500 or L5501 coil missing?

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i have added SSD to the system long time ago when i got it and my graphic card was replaced. i can't pinpoint when i have noticed that something is not working right, was it right after graphic card replacement or some update of OS since i was not using this iMac that much after that repair.

由 Predrag 完成的 2018年5月31日

@danj can you please tell me how to know if the coil is damaged or not? i am planing to open up the iMac in few hours.

由 Predrag 完成的 2018年7月25日

I physically damaged mine ;-{ Tore it off the logic board. Take a good hi res pic of the area so we can see and paste it here if you don't see it missing.

由 Dan 完成的 2018年7月25日

I was lucky! I had a junker to steal the part from. I can tell you both L5500 & L5501 are 220-OHM Ferrite Beads

Here's one source: Mouser - Passive-Components - EMI-Filters

Here's a spec sheet: Inductor Type Chip Ferrite Beads

由 Dan 完成的 2018年7月26日

hey @danj could you help me out figuring exact one i should order, i tried to find them locally here in Serbia but had no luck, probably Ferrite Beads are called differently in my language, plus i am no electrician so i have no clue what to ask for and even what to order from that website... or i can use any from that list you gave me?

Thanks a lot for all your help.

由 Predrag 完成的 2018年7月27日

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Not enough info here to help.

Did you run diagnostics on the system? Also down load this app: TG Pro so you can monitor the systems thermal sensors and fan. Tell us the error from AHT and snap a screenshot of the full main window (you may need to expand it a bit to get all of the sensors visible) and paste it here for us to see. 在已经存在的问题里加入图片

You also spoke about replacing the GPU card what card is your system using now? — Dan
i get this error in AHT: 4sns/1/c0000008: TAOP--124

i have also purchased replacement sensors some time back, 2 of them and tried replacing it, tried both of them and problem is still there.

I have uploaded screenshot from TG Pro, my fans are going berserker since Macs Fan Control won't start atm...

I have just reinstalled Macs fan control and took snapshot from it's sensor readings.

also i have just uploaded images from cinebench from both mac osx and windows 10 for reference.

ill try to put longer AHT now to do it's magic. — Predrag
i have added SSD to the system long time ago when i got it and my graphic card was replaced. i can't pinpoint when i have noticed that something is not working right, was it right after graphic card replacement or some update of OS since i was not using this iMac that much after that repair. — Predrag
@danj can you please tell me how to know if the coil is damaged or not? i am planing to open up the iMac in few hours. — Predrag
I physically damaged mine ;-{ Tore it off the logic board. Take a good hi res pic of the area so we can see and paste it here if you don't see it missing. — Dan
I was lucky! I had a junker to steal the part from. I can tell you both L5500 & L5501 are 220-OHM Ferrite Beads

Here's one source: Mouser - Passive-Components - EMI-Filters

Here's a spec sheet: Inductor Type Chip Ferrite Beads — Dan
hey @danj could you help me out figuring exact one i should order, i tried to find them locally here in Serbia but had no luck, probably Ferrite Beads are called differently in my language, plus i am no electrician so i have no clue what to ask for and even what to order from that website... or i can use any from that list you gave me?

Thanks a lot for all your help. — Predrag

score 1 · Answer 1 · 2018-05-15T07:24:23-07:00

mayer @mayer

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Boot it up from an external USB drive running El Capitan. Did this happen after an Apple update?

This is what I had to do to a 2012 27" iMac that had done the same thing as yours.

The 10.11 runs perfectly.

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i will try that, will report back. also I have tried various versions of OS X and same thing is happening, but I have always booted from ssd and installed OS X, how can I boot from USB stick?

由 Predrag 完成的 2018年5月31日

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iMac Intel 27" EMC 2429

GPU/CPU working at 50%

Update (07/26/2018)

Update (11/12/2018)

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Update (05/31/2018)

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