2019 iMac - i5 vs i9? Cooling and Throttling?

Black Diesel

macrumors regular
Original poster
Mar 15, 2011
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I've seen a lot of talk about cooling and throttling....does this mean that if apple didn't change the cooling system for the iMac, then an i5 might perform as good as a "throttled" i9?
 

Rockadile

macrumors 6502
Jun 11, 2012
467
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I've seen a lot of talk about cooling and throttling....does this mean that if apple didn't change the cooling system for the iMac, then an i5 might perform as good as a "throttled" i9?
It could be identical or worse if the i9 can't go up near its boost speed again after being throttled. The iMac Pro can at least let the CPU raise its clock speed higher before being throttled again.
 
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TheTuesdaydude

macrumors newbie
Jun 11, 2013
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I've seen a lot of talk about cooling and throttling....does this mean that if apple didn't change the cooling system for the iMac, then an i5 might perform as good as a "throttled" i9?

Depending on what you are doing the throttled i9 can still outperform the i5, i5=6core and i9=16core.
 

fokmik

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Oct 28, 2016
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i9 and vega, both run cooler than the rx 580X and i7/i5 9xW thanks to the thermal paste into the chip itself
Some tests also Screen Shot 2019-03-22 at 12.25.01.png
 

TheTuesdaydude

macrumors newbie
Jun 11, 2013
20
8
i9=8 cores, 16 threads. you can't count it as if it's a 16 core cpu.

Thats right, my bad sorry! Still if you have a workflow or applications that can handle more then 6 threads, then a throttled i9 still outperforms the i5.
 

SkiHound2

macrumors regular
Jul 15, 2018
231
163
i9 and vega, both run cooler than the rx 580X and i7/i5 9xW thanks to the thermal paste into the chip itself
Some tests also View attachment 827651

But I believe the 9th generation i5 (9600k, used in the new iMac) also uses different cooling (ie. solder and heat spreader) than the previous generation cpus. You're comparing the 9th generation i9 to 8th generation i7 in the graph.
 

Fishrrman

macrumors Core
Feb 20, 2009
20,186
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This subject is "an unknown issue" yet.
We won't know until actual production models get into the hands of users, and actual reports appear.
 
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adamjackson

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Jul 9, 2008
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I look forward to to an iFixit teardown to show Apple took design changes into account on the new iMacs to either adopt an iMac Pro like config or slap a larger heat spreader onto the i9 model.
 
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dazlicous

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Jun 2, 2011
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I look forward to to an iFixit teardown to show Apple took design changes into account on the new iMacs to either adopt an iMac Pro like config or slap a larger heat spreader onto the i9 model.
Exactly and until then I wouldn’t even consider placing an order

I want a 27” iMac maxed out especially CPU and GPU but I ain’t in no rush to buy. If the cooling isn’t any better I will just wait. My 2013 rMBP is still going strong but I would like a desktop one day
 
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fokmik

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But I believe the 9th generation i5 (9600k, used in the new iMac) also uses different cooling (ie. solder and heat spreader) than the previous generation cpus. You're comparing the 9th generation i9 to 8th generation i7 in the graph.
still the i9 has that thermal paste integrated, the i5 9th gen that is only available into the highest imac default "3.7 ghz 6C" the rest being 8th gen has 91W but separate thermal paste
Still, to have 10-15C colder cpu i9 8 cores than any quad core i7 is impressive and helps with the current imac chassis
I think if Apple put the imac pro cooling, this i9 never passed 75C
 

xWhiplash

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Oct 21, 2009
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I got the i5 3.8Ghz 2017 iMac and I have regretted it for my video encoding with FCPX. Now the new i5 has more cores. Would the i9 still be best even if it does throttle?
 

propower

macrumors 6502a
Jul 23, 2010
726
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I got the i5 3.8Ghz 2017 iMac and I have regretted it for my video encoding with FCPX. Now the new i5 has more cores. Would the i9 still be best even if it does throttle?


Curious - why do you regret the 3.8 for video encoding? Do you wish you would have got the i7? iMacPro?
 

xWhiplash

macrumors 68030
Oct 21, 2009
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Curious - why do you regret the 3.8 for video encoding? Do you wish you would have got the i7? iMacPro?

I wish I got the i7 for the additional performance. I don’t like the iMac Pro due to lack of QuickSync for video encoding.
 

Rockadile

macrumors 6502
Jun 11, 2012
467
188
I got the i5 3.8Ghz 2017 iMac and I have regretted it for my video encoding with FCPX. Now the new i5 has more cores. Would the i9 still be best even if it does throttle?
That's the million dollar question we are waiting for the tech reviewers to answer ;)
 

Black Diesel

macrumors regular
Original poster
Mar 15, 2011
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28
That's the million dollar question we are waiting for the tech reviewers to answer ;)

So the reviews will expose any i9 throttling that occurs and compare the performance of the "throttled" i9 to the non-throttled high end i5? Or, do they both get throttled? Sounds like most people are waiting to see this to figure out which configuration is best to order....hopefully soon!
 
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androo4519

macrumors newbie
Jan 26, 2005
26
21
I'm waiting for reviews too. If the i9 offers no real advantage, and maybe one or two disadvantages, I'll go for the 9th gen i5 and spend the money on the Vega 48 instead. I'm in a bit of a quandry because I mainly do photo editing but want to get more into video – do I max out the processor or the graphics card? If I do both the price goes above what I'm comfortable with. Logic says I should spend on the processor and if video becomes more important I can add an external graphics processor later. I can never upgrade the CPU. Need to know the performance difference between the 580 and the Vega 48 before I buy. As well as the difference between the top end i5 and i9.
 

JohanCruyff

macrumors member
Nov 14, 2007
44
6
Italy
Is it possible that Apple adopts the 9900KF version of the i9 processor (no integrated graphics but several degrees cooler than the 9900K)?

In a similar way, the traditional i5 9600K could be replaced by a cooler i5 9600KF in the iMac.
 

vaugha

macrumors 6502a
Nov 3, 2011
598
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I'm going to watch this thread closely. Another inevitable topic that was bound to show up.
 

fuchsdh

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Jun 19, 2014
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I wish I got the i7 for the additional performance. I don’t like the iMac Pro due to lack of QuickSync for video encoding.

This seems like a rather weird issue to have with the iMac Pro. Unless all you're doing is H.264/5 encodes, you're still going to be saving a ton of time on everything up to the final export.
 
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xWhiplash

macrumors 68030
Oct 21, 2009
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This seems like a rather weird issue to have with the iMac Pro. Unless all you're doing is H.264/5 encodes, you're still going to be saving a ton of time on everything up to the final export.
The final export is where I need to save the most time.
 

macduke

macrumors G4
Jun 27, 2007
11,080
14,906
Central U.S.
I've ran some tests on my new iMac with i9. Results:

Cinebench R15: 1662
Cinebench R20: 4067

Geekbench Single: 6394
Geekbench Multi: 33690

Can't get the fans to ramp. Running quiet.

Rendered a 22,000 MP oak tree in Photoshop (yes, 22 giga pixels) and it took it 10 minutes but it never got loud.

In Premiere Pro I'm currently running Warp Stabilizer (default settings) on 5 minute 4K clip I shot on my iPhone XS today with my daughter exploring the woods behind our house. It's saying it's going to take 53 minutes and it hasn't gotten noisy yet. I haven't done much with video in a long time but have been wanting to and I figured this would be an operation that would use a lot of processing. Thoughts on this? I figured it would be at least a little bit loud. I might start stacking lots of background apps now while I'm waiting.
 
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