Possible to replace the GPU of a Late 2014 Retina iMac?

lars666

macrumors 6502a
Original poster
Jul 13, 2008
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863
Since a few weeks, I have huge problems with my Late 2014 27" Retina GPU (AMD Radeon R9 M295X 4GB) – it overheats within seconds/minutes, even with minimal load when only playing a YouTube video or similar. Shooting up to 100° celsius very fast, often even reaching 115° celsius and more, shutting down itself soon after that. No failing graphic card symptoms like green bars, coloured blocks or whatever on the screen though.

I brought the iMac to a third party repair service which is not Apple-certified, but – judging by its reviews – a reputable chain in my town with a few stores. Was hoping that the iMac only needs to be cleaned of dust inside with new heat sink paste applied, but instead they told me that the GPU chip is already damaged and needs to be changed. Will cost $400 – a lot of money, but I accepted the repair offer nevertheless. I know it's a quite old mac, but it was maxed out back then, and it's still a better deal for me than trying to sell it with a faulty GPU.

Although I thought having read that the GPU can be only replaced in iMacs up to 2013 or so, I didn't question the info they gave me. Now that I am waiting for the repair to be done and having googled the topic again, I am more and more wondering: Can the GPU REALLY be replaced – or is it possible they lied to me so that I pay the $400 and the solution is much simpler, like "only" cleaning the fan / reapplying the heat paste?

I have no real reason to distrust them – again: They make a very professional and reputable impression – but as I find no real evidence that the AMD Radeon R9 M295X in my iMac can be replaced (more so the contrary), it would give me peace of mind if someone here can confirm that it's possible.

Thanks so much in advance!
 
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mikehalloran

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Oct 14, 2018
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The Sillie Con Valley
Anything can be repaired but is it worth it? This is not very common as you already know. Once a component fails that quickly, it is highly doubtful that refreshing the heat sink will make it run as before. If you have that done only and it doesn't work, the money is gone.

If you were willing to do it yourself, that's different.

If you have the work done, it's the perfect time to give it an upgrade. You can give this a nice speed boost for not much money by installing an NVMe 3 x4 blade. Because of the PCIe 2 bus, a slow blade like the Intel 660p ($236 for 2TB) is enough — an expensive, fast blade like the 970 EVO will not be any faster. There's a wake from sleep issue but a simple terminal command gets around that. Throw away the HDD. Replace the battery as long as you're in there.

Bottom line is that you're going to have to sink some money into this to keep it going. Do you want to do it with this or is it really time for a new iMac?
 

lars666

macrumors 6502a
Original poster
Jul 13, 2008
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863
Thanks a lot for the answer, appreciated. I also thought about upgrading to "real" SSD if the iMac is opened anyway – however I've decided that I'm fine with the speed of my stock fusion drive. I understand what you're trying to say, but (IMO) investing those $400 to be able to use my "old" iMac still a few more years (which otherwise works perfectly fine for me and my task – I probably wouldn't even notice much speed bump with a brand new one) still is the financally better choice than selling the iMac with a failing GPU and buy a new one. I surely don't want to invest in any other upgrades though, I just want and need to have it repaired. $400 is more than my initial expected $150 cleaning / heat paste renewal, but I am even fine with that – IF I was really told the truth that the graphic chip has to be replaced and will be replaced. That's the reason I am asking here – because I became very unsure after reading more like "it isn't replacable" tenor now when googling.
 

mikehalloran

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Oct 14, 2018
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however I've decided that I'm fine with the speed of my stock fusion drive.
Who says that the HDD isn't what caused the problem? If yours was a 2009–2012, I'd be telling you that it was but Apple did put in a slower, cooler HDD in the 2013–2014. Then they put in an even slower and cooler HDD again in the 2015–current. They did this to reduce the strain on other components caused by heat.

I'd have to see it on my bench to know for certain but... The HDD is 5 years old — when new it would have had a 2 year warranty if sold on the aftermarket.

Since a 2TB 660p costs about the same as a 2TB SATA III SSD but runs 6x faster, it's the better choice if keeping this for a number of years.

There is no way that, once opened, I'd keep an HDD in that Mac.
 

lars666

macrumors 6502a
Original poster
Jul 13, 2008
990
863
Definitely not the HDD causing the GPU overheating – everything worked fine until a few weeks ago. (The HDD is now two years old, by the way, as it was replaced within Apple Care protecting after about three years.)

Again, as explaned: I really just want to have my iMac repaired to what it was before ... :) $400 is IMO at the fence for my 2014 iMac, but if replacing the GPU chip is necessary (and really done), I'm willing to bite in the sour apple. You can believe me that I calculated the alternatives of selling it and already buy a new one or upgrading it for even more money than the repair costs for a longer future proof.
 
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