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MacBook Pro i5 running at only 800mhz.

drewwils

macrumors newbie
Original poster
Jun 10, 2018
3
1
Extreme lag on a used 2011 MacBook Pro I bought for my parents. Intel Power Gadget shows CPU is running at 800mhz with no fluctuation. Zero. Booted into diagnostics and no problems were found. Can't return it.

Any ideas?
 
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drewwils

macrumors newbie
Original poster
Jun 10, 2018
3
1
what is the temperatures when the machine is running?
Since this is presumedly newly bought, is it a clean install?
What is the battery status?

Clean El Capitan install on a new SSD. No battery - only used as a desktop. Strange, temperature is ~64°C (149F) on Amazon Prime Video ~50% load and streaming Xfinity (Flash) using ~85% load and extreme lag.
 
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iMacC2D

macrumors 6502a
Jun 24, 2010
621
286
Clean El Capitan install on a new SSD. No battery - only used as a desktop. Strange, temperature is 64°C (149F) on Amazon Prime Video ~50% load and streaming Xfinity (Flash) using ~85% load and extreme lag.

That's the problem. The machine throttles the CPU back significantly with no battery installed.
 
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Schranke

macrumors 6502a
Apr 3, 2010
942
958
Copenhagen, Denmark
That's the problem. The machine throttles the CPU back significantly with no battery installed.
Yep, the battery acts as a power reserve to provide burst energy when needed (not often) the machine will throttle to prevent draining more than can be provided by the adapter.
I once stumbled upon a thread which talked about how to modify this feature.
Here are a links to get you started (This is at your own risk, personally I would just get a new battery)
https://apple.stackexchange.com/que...step-when-using-macbook-pro-without-a-battery
Edit: a few more links
https://arstechnica.com/civis/viewtopic.php?f=19&t=1392381
https://www.insanelymac.com/forum/topic/306819-disable-speedstep-on-a-late-2011-mbp-with-yosemite/
 
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elathus

macrumors newbie
Sep 1, 2015
6
4
Has to be an original battery I think, otherwise it will keep throttling. Lost a couple of days over this just a week ago, before figuring it out.
 

Schranke

macrumors 6502a
Apr 3, 2010
942
958
Copenhagen, Denmark
Has to be an original battery I think, otherwise it will keep throttling. Lost a couple of days over this just a week ago, before figuring it out.
What do you mean by original battery?
I changed one I my moms Mac with a replacement from ifixit, that is not an original battery, but I did not see any limitation on performance.
 
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elathus

macrumors newbie
Sep 1, 2015
6
4
I believe ifixit sells OEMs, which are basically originals, not so cheap replacements from ebay/aliexpress. But it seems like it differs from mac to mac. 2010 mbp at work works just fine without battery. Mine 2015 throttled.
 

Count Blah

macrumors 68040
Jan 6, 2004
3,117
2,597
US of A
I have used "non-original" batteries, and have had it work. Check 'Power' or 'Battery' under 'About this Mac' and tell us what it says for battery health information.
 

elathus

macrumors newbie
Sep 1, 2015
6
4
If it's not the battery, if it's not overheating, then it's probably one of the sensors on the motherboard. I got lucky the problem being just the battery.
 
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