I recently brought an iMac 27" 14,2 back to life after a CPU fault (which in itself was odd since I never seen a PC or Mac with a fried Intel CPU) and it runs pretty nice ... but on a Intel Core i3 4130 which leaves a lot to desire in terms of performance.

i'm thinking of replacing it with an i5 or i7 - but then I've seen that Xeon 2013 Xeon's are quite cheap and was wondering if the iMac Mainboard can run with it.

Does anybody knows if such upgrade is possible? E3 1150 Xeon's are basically i7s without the GPU but more cache and offer better per watt performance.


I will test 3 different CPU's with the iMac 27 14,2 mainboard, despite the the answer below. The information I found is not conclusive and well... why not?

I was able to grab 3 CPU's for testing, however the 1285 is not something you can call cheap alternative to i7 ;-)

  • Xeon E3-1231v3
  • Xeon E3-1285v3
  • Core i7 4790K

Once tested I'll share the results here, incl. some pictures. The CPU cooling block CPU/GPU hybrid is quite difficult to mount and one need to be really careful with it - something ifixit and others don't mention.

  • 2
    Will you really notice a better "per watt" performance on a large desktop like that - even if the upgrade was possible, which Allan has pointed out isn't?
    – Solar Mike
    Commented Oct 29, 2017 at 22:14
  • 1
    Can you post a specific xeon you have in mind? I can't seem to find one that can either rival 4771's 3.9GHz or meaningfully undercut it's 84W power budget. (skimming 4W hardly counts, shutting down the GPU likely saves more).
    – Agent_L
    Commented Oct 30, 2017 at 9:23
  • Take this one for example: ark.intel.com/products/80910/…
    – PJJ
    Commented Oct 30, 2017 at 19:22
  • If I had to choose between Core i7 and Xeon - I would pick Xeon, but you are right, anything less ~10W won't really matter.
    – PJJ
    Commented Oct 30, 2017 at 19:25

1 Answer 1


It will not work with a Xeon processor.

The CPU you should get is anything from the Haswell line of CPUs. If I were doing the upgrade, I would install an Core i7 (4771).

  • Are you absoulute sure about that? I want to try this CPU ark.intel.com/products/80910/…
    – PJJ
    Commented Oct 30, 2017 at 19:19
  • If I am not mistaken, a Xeon processor needs ECC memory. 1) those are few and far between in SO-DIMM form factor and 2), there's no documentation stating that the iMac will support this type of memory.
    – Allan
    Commented Oct 30, 2017 at 20:45
  • You are mistaken, ECC memory is optional, all motherboards and processors support non ECC unbuffered ram.
    – PJJ
    Commented Oct 30, 2017 at 23:33
  • What you can't do is mix ECC with non-ECC, since that can't work. Unbuffered ECC is actually slower then Unbuffered non-ECC DIMM's (which is confusing since one would think it's the other way around when ECC is done through CPU cache) - so if you are not running a rendering farm - you won't care a lot about ECC, and you can run non-ECC DIMM's in Mac Pro, the CPU doesn't care.
    – PJJ
    Commented Oct 30, 2017 at 23:57

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