Early results, no thermal throttling on i9 iMacs

jinnyman

macrumors 6502a
Sep 2, 2011
580
516
Lincolnshire, IL
Based on the second video, continuous load makes CPU clocks at around 3.7~3.8.
My custom PC i9-9900k with air cooling (NH-D15) runs continuous 100% load at 4.7. (no overclocking)
No wonder it's able to maintain higher than base, because it's only several hundred above the base clock speed.
 

kaintxu

macrumors regular
Jul 9, 2018
178
75
Edinburgh
Well based on the first video, with the GPU stress test it seem to get quite hot. Maybe not enough to thermal throttle, but fan ramps up hard. You can even hear it in the video.
 

MandiMac

macrumors 65816
Feb 25, 2012
1,261
657
Well, everything above the base clock is technically automatic overclocking. Throttling would be the process of being under the base clock. Not reaching the highest Turbo Boost level is not throttling. Case closed.
 

BigBoy2018

Suspended
Oct 23, 2018
964
1,822
Well, everything above the base clock is technically automatic overclocking. Throttling would be the process of being under the base clock. Not reaching the highest Turbo Boost level is not throttling. Case closed.

This is why my preference is to get the processor with the higher base clock speed and then use something like turbo boost switcher to turn off turbo boost when I'm doing any long video render or export.

With turbo boost on, the fans run up, but I've discovered these long renders don't actually take any less time.

With turbo boost disabled, the machine stays quieter and cooler and stays at the 3.8ghz clock speed throughout.

To me, turbo boost is a little tweak that helps in very brief actions, and something that basically 'tricks' Geekbench and makes the processor seem faster, but for any extended use, it's the base clock speed that is going to be what you need to key in on.
 

gusping

macrumors 65816
Mar 12, 2012
1,069
725
London, UK
Based on the second video, continuous load makes CPU clocks at around 3.7~3.8.
My custom PC i9-9900k with air cooling (NH-D15) runs continuous 100% load at 4.7. (no overclocking)
No wonder it's able to maintain higher than base, because it's only several hundred above the base clock speed.

Off topic, but is the NH-D15 sufficient to keep the 9900k cool while gaming etc? Very impressive if so.
 
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jinnyman

macrumors 6502a
Sep 2, 2011
580
516
Lincolnshire, IL
Off topic, but is the NH-D15 sufficient to keep the 9900k cool while gaming etc? Very impressive if so.
Yup. I haven't overclocked the i9 yet so it's running at 4.7 all core turbo. During the heavy gaming session (Apex Legend for example), the temp reaches maximum of 82~3 deg celsius, and usually at mid 70s. I've also made sure the continuous air flow is maintained from the front of case to back though.
 

kaintxu

macrumors regular
Jul 9, 2018
178
75
Edinburgh
Yup. I haven't overclocked the i9 yet so it's running at 4.7 all core turbo. During the heavy gaming session (Apex Legend for example), the temp reaches maximum of 82~3 deg celsius, and usually at mid 70s. I've also made sure the continuous air flow is maintained from the front of case to back though.

Is Apex Legend very demanding. I wanted to try it once I got my new iMac. Do you think it will run?
 

jinnyman

macrumors 6502a
Sep 2, 2011
580
516
Lincolnshire, IL
Is Apex Legend very demanding. I wanted to try it once I got my new iMac. Do you think it will run?
I run the game at 4k UHD resolution with max setting. You won't be able to run it at 5k of course, but on bootcamp with WQHD or something, you should be able to run pretty well with option adjusted for better performance.
 

Kaelis

macrumors newbie
Mar 28, 2019
14
24
Apex runs at 52.4FPS average in 1440p/High settings on the RX580 (source gamernexus). The Vega 48 should be plenty fine for 1440p/60FPS in High/Ultra !
 

kaintxu

macrumors regular
Jul 9, 2018
178
75
Edinburgh
I run the game at 4k UHD resolution with max setting. You won't be able to run it at 5k of course, but on bootcamp with WQHD or something, you should be able to run pretty well with option adjusted for better performance.
my current iMac is not 5k, so never used one.

Is it better to run game on 4K or 1440p which is native to the 5k?
[doublepost=1554044492][/doublepost]
Apex runs at 52.4FPS average in 1440p/High settings on the RX580 (source gamernexus). The Vega 48 should be plenty fine for 1440p/60FPS in High/Ultra !

Will it be the same with the 9600K as with the 9900K if with a vega?
 

Bohemien

macrumors regular
Mar 28, 2019
136
81
Germany
I left my i9 maxed out today for a good few hours, never dropped below 3.6Ghz clock speed - unlike my i9 macbook pro *insert annoyed face here*.

The iMac is also a lot quieter than my iMac Pro, which surprised me a bit.

Which graphics card do you have?
 

smetvid

macrumors 6502
Nov 1, 2009
451
216
Based on the second video, continuous load makes CPU clocks at around 3.7~3.8.
My custom PC i9-9900k with air cooling (NH-D15) runs continuous 100% load at 4.7. (no overclocking)
No wonder it's able to maintain higher than base, because it's only several hundred above the base clock speed.

Which is still not throttling. It just doesn’t make use of turbo boost as much as your custom PC. I’m not really concerned with what a larger custom tower PC can do with a CPU. I’m more concerned will how it compares to other Macs.
 

jinnyman

macrumors 6502a
Sep 2, 2011
580
516
Lincolnshire, IL
Which is still not throttling. It just doesn’t make use of turbo boost as much as your custom PC. I’m not really concerned with what a larger custom tower PC can do with a CPU. I’m more concerned will how it compares to other Macs.
I agree that it's not throttling by anymeans. But it nevertheless show less performance than perceived from naming though.
As I stated in other thread, I'm content with iMac's limited tdp i9 as iMac is meant to be silent work horse AIO. Apple could've done better by chaging cooling scheme, but with the same design I doubt it can reach a real turbo anyway.

Just don''t do this kind of thing on Mac Pro and I'm fine with Apple.
 

kaintxu

macrumors regular
Jul 9, 2018
178
75
Edinburgh
I run the game at 4k UHD resolution with max setting. You won't be able to run it at 5k of course, but on bootcamp with WQHD or something, you should be able to run pretty well with option adjusted for better performance.

Is that on the I9 with Vega 48?

As I mentioned before, how does 4k look on the 5k monitor? my current iMac is a 2011, so no idea how 5K scales. All I know is that it is proportional to 1440p more than 4k, and heard is better to run the games like that?
 

WrightBrain

macrumors regular
May 30, 2009
134
167
With turbo boost on, the fans run up, but I've discovered these long renders don't actually take any less time

Hey, I was concerned about heat and was considering using Turbo Boost Switcher as well. How much does It decrease performance? Is it noticeable?

Do you turn off TB for games?
 

BigBoy2018

Suspended
Oct 23, 2018
964
1,822
Hey, I was concerned about heat and was considering using Turbo Boost Switcher as well. How much does It decrease performance? Is it noticeable?

Do you turn off TB for games?

Yes, games like fallout which are demanding, I do turn it off.
Also for long video remders. Witb a video remder i can turn it on and off and almost immediately when i turn it on the temps jump up and the fans go from 1200 or so rpm to 1800 or so rpm.
It doesnt however have any impact of the ‘estimated time remaining’ of the render.
Thats made me kind of conclude that turbo boost is a bs teick to make a processor look better in benchmarks, but is borderline useless in the real world. Thats why i now will always looks for the hiher clock speed of a certain generation of chip, and ignore tha geekbench scores for the most part.
 
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