Can the 2015 5k imac be upgraded from i5 6600 to I7 7700?

BigHungry

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Jul 1, 2017
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Both CPU's are 1151 sockets but I am not sure if it is a direct drop in replacement possible. they are both 65w CPU's so there should not be a heat issue, my only question is if the bios will support it? and will it support the DDR3 memory used?
 

thekev

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Aug 5, 2010
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It's hardly worth it. The difference between cpus of the same generation rarely justifies the cost or the possible denial of repairs if some other part of the machine fails at a later time.
 
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BigHungry

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Jul 1, 2017
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It's hardly worth it. The difference between cpus of the same generation rarely justifies the cost or the possible denial of repairs if some other part of the machine fails at a later time.
But doesn't hyper threading help the mac because it is a Unix based OS?
 

thekev

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Aug 5, 2010
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But doesn't hyper threading help the mac because it is a Unix based OS?
Windows can make use of hyperthreading too. What makes you think only Unix makes use of it? Hyperthreading is used to reduce core starvation, but it doesn't automatically make things faster. Sometimes it makes them slower. It would (for a low level example) be undesirable in cases where some process is designed with L1 blocking in mind. In that case a hyperthreaded version may run slower.

I'm curious, have you identified a particular bottleneck with your current system that would motivate this upgrade in the first place?
 

BigHungry

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Jul 1, 2017
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No, I guess I was just caught up in the hype that an I7 with hyper threading is so much better then one without, so I guess your saying that the i5 6600 3.5 GHz CPU in my 27" 5k i mac will not see much improvement going to a 4ghz i7 with hyper threading?
 

trsblader

macrumors 6502
May 20, 2011
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No, I guess I was just caught up in the hype that an I7 with hyper threading is so much better then one without, so I guess your saying that the i5 6600 3.5 GHz CPU in my 27" 5k i mac will not see much improvement going to a 4ghz i7 with hyper threading?
The answer is: it depends. Are you doing tasks like rendering or video editing that can make effective use of hyper-threading? Hyper-threading isn't just automatically being used 24/7 to make everything faster. Surfing the web and watching YouTube, for example, isn't going to take advantage of hyper-threading, and even most games don't take advantage of it. The general take away is about 20-40% better performance of hyper threading over the same non-hyper threaded CPU, while doing tasks that take advantage of it.

thekev asked a good question and really the one you need to answer before thinking of upgrading: do you currently have a bottleneck in the CPU? Are things you're doing currently utilizing 100% of all of your current cores?
 

thekev

macrumors 604
Aug 5, 2010
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No, I guess I was just caught up in the hype that an I7 with hyper threading is so much better then one without, so I guess your saying that the i5 6600 3.5 GHz CPU in my 27" 5k i mac will not see much improvement going to a 4ghz i7 with hyper threading?
It varies. Hyperthreading helps when a cpu core spends too much time idle. If this is not the case or the code being executed is highly cache sensitive, it can be slower. Here's a math library example.

Also what are you doing with it? A higher clocked cpu with hyperthreading only benefits some people. If you're going to break open an imac, you will probably lose any options for cheap repairs if anything goes wrong later (Apple usually offers depot repair for $300). Apart from that the cost of the cpu itself is likely to be non-trivial.

I'm skeptical whether you will really see any gain that justifies the purchase or it's just a desire for something newer or better.