MacBook Pro 2015 Retina 13inch CPU Performance

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Level 1

8 points

MacBook Pro 2015 Retina 13inch CPU Performance

Hi,

anyone knows how much Watts does Apple set for the CPU on a 2015 MacBook Pro Retina 13inch (i5-5257U)?

It seems Apple has limited the power draw of this CPU to 18 Watts instead of 28 Watts (rated by Intel). An early review article on Internet (https://www.notebookcheck.net/Apple-MacBook-Pro-Retina-13-Early-2015-Notebook-Review.139621.0.html) even said that the CPU was limited to 32 Watts, which is higher than the Intel rate.

The CPU on my MacBook Pro would only use up to 18 Watts of power and the system total power usage is well below 35 Watts with a 65 Watt PSU connected and CPU Core temperature under 85 Degrees C (fan speed 80%) while running Cinebench R23. Therefore I believe there is something limiting the CPU performance. I am running the 11.2.3 Big Sur.

As I didn't recorded the CPU power draw before, and I noticed this issue recently, I wonder if Apple is lowering the CPU performance of older Macs to accelerate the sale of new units.

MacBook Pro 13″, macOS 11.2

Posted on Apr 2, 2021 6:10 AM

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Answer 1

HWTech

Level 9

68,312 points

Apr 2, 2021 12:48 PM in response to Chipei

It is certainly possible that Apple has limited the CPU in order to maintain proper cooling on the laptop, but I'm not sure they were doing so on the 2015 model. I'm sure I read about this happening with some of the higher end Apple laptops (i9?) because the Apple Retina laptops are so thin making it hard to keep the CPU within safe thermal parameters. I know that the later laptops have the CPU throttled once the fans have reached maximum speed and the temps reach 100C in order to keep the thermals at proper levels. This may be what is occurring. I've really only concerned myself with monitoring idle temps and max temps under extreme load as that is all that really matters for me when servicing systems.

If the CPU is not using a lot of power or running at full speed (aka frequency), then it may indicate a power issue (or the CPU is being temporarily throttled due to a thermal issue). A bad battery could cause the system not to receive the full power of the charger. Option-click the battery icon to check the condition of the battery. Also run the Apple Diagnostics to see if any hardware issues are detected.

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Answer 2

Chipei Author

Level 1

8 points

Apr 18, 2021 9:03 AM in response to HWTech

Hello,

thank you for your reply. Recently because of the lagging and throttle issues I get my System back to High Sierra, with a clean install (new format the SSD and co.), I still experiencing the issues as I described before.

I ran Apple Diagnostics, nothing found.

I reset SMC and PRAM, NVRAM. I also disconnected the battery and power from the MBP for about 30 min, to reset any possible chips.

I cleaned the internal and reapplied thermal paste (MX-4) of the CPU, didn't help.

The battery in this MBP was replaced by Apple in Winter 2019 which is in pretty good shape, coconutBattery shows 99% battery health.

The CPU gets about 1820 points in Cinebench R23, the CPU temperature during that marking, stays at, as described before, around 80 Degrees C with fan speed at about 4k RPM (full speed is 6.2k RPM), so the temperature is definitely ok and well below the limit which could lead to thermal throttle. The power draw of the whole system, include full brightness screen, is around 35 Watts.

The frequency of the CPU often reach 3GHz with only about 8 Watts power consumed. Pretty weird.

The frequency of the Iris GPU stays low always, no matter if I will watch a Movie, YouTube or anything, the frequency of the GPU won't go above 600 MHz.

I also discovered that the Mac doesn't have any performance differences if the AC is disconnected. (same power draw and same Cinebench Score with battery). It seems that the power supply does nothing than charge the battery and the Mac still uses power from the battery although it is connected to AC.

Could that be a faulty or failing Power Supply which caused those issues?

Or it is on software Level? .kext or SpeedStep issue?

Greetings

Chipei

*Edit: Boot-Rom of my MBP is 426.0.0.0.0, SMC Firmware is 2.28f7. Those should be the current firmware for my machine.

the performance drop of the MBP is sometime painful because I can't use my Mac with its full potential. It would even get laggy when I want to play Netflix or Amazon Prime-Video with full screen. At first I thought it might be the OS but after downgrade to High Sierra, well situation gets a bit better, but not much improvement.

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MacBook Pro 2015 Retina 13inch CPU Performance

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