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SharonT
Blue Screen Again
Posts: 7
Registered: ‎09-15-2015
Location: Israel
Views: 714
Message 11 of 17

Re: Yoga 910 cpu throttling to 400 mhz

I see in the BIOS these 2 lines:
BIOS Version 2JCN39WW
EC Version 2JEC36WW

Does this mean I have 39WW or 36WW?
lucky93
Punch Card
Posts: 48
Registered: ‎02-14-2017
Location: US
Views: 710
Message 12 of 17

Re: Yoga 910 cpu throttling to 400 mhz

You have the latest bios update 2JCN39WW

danwat12341
Blue Screen Again
Posts: 20
Registered: ‎01-30-2014
Views: 677
Message 13 of 17

Re: Yoga 910 cpu throttling to 400 mhz

How can I get a copy of BIOS 28ww to reduce throttling?

I got the Yoga 910 7500u with the '39' BIOS and at full load with Prime95, or with Acronis True Image when making a backup, it'll crash throttle to 400MHZ for about 5 seconds, and then back up to 2.7GHZ or so for about 15 seconds, and then repeat. Not good if I am doing time sensitive activities such as day trading.

This was this the power profile set to either balanced or high performance. Is quiet mode and option within that or somewhere else so I can make sure that is disabled? I don't think i've heard the fans ever be at full speed.

The throttling is so bad when it crashes to 400MHZ, you know it has downclocked way too much because the fans slow down every time it happens!

lucky93
Punch Card
Posts: 48
Registered: ‎02-14-2017
Location: US
Views: 668
Message 14 of 17

Re: Yoga 910 cpu throttling to 400 mhz

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danwat12341
Blue Screen Again
Posts: 20
Registered: ‎01-30-2014
Views: 657
Message 15 of 17

Re: Yoga 910 cpu throttling to 400 mhz

Thanks, yes Reggie of the Lenovo Facebook page said to just rename the file path once I get the url from the drivers downloads page for the laptop in order to download the version I wanted. Goes down to version 27

But when I launch the program, it says the BIOS version I have installed is newer than the one it has to install, so it will not do it. I can goto \users\username\appdata\local\temp\7z***** and find the extracted contects of the BIOS update file, but have not found the correct parameter to change in there yet to allow it downgrade the BIOS version. 

 

Version 39 that my laptop came with, the fans won't even go to highest speed when it is fully loaded or throttling. I heard it briefly once during boot while it was trying to recognize a USB device before beginning to boot Windows. 

So, this BIOS version sucks. 

Thanks

lucky93
Punch Card
Posts: 48
Registered: ‎02-14-2017
Location: US
Views: 652
Message 16 of 17

Re: Yoga 910 cpu throttling to 400 mhz

You have to go to bios settings and enable bios downgrade in order to downgrade.

danwat12341
Blue Screen Again
Posts: 20
Registered: ‎01-30-2014
Views: 642
Message 17 of 17

Re: Yoga 910 cpu throttling to 400 mhz

Yes I realized that although on some forum it mentioned changing a parameter in the flasher. And in order to enter the BIOS, there is no keyboard key, it is a button on the side you press with a paper clip when the machine is off. It'll turn on and bring up the menu with an option to configure the BIOS.

 

In the BIOS is a DPTF thermal management settings; quiet mode, balanced and high performance mode. 

In the '28' version of the BIOS there is only the latter 2. High performance mode in the newest BIOS (39), the fans will not reach full speed even if the CPU cores are in the high 80s/90s C. The old '28' BIOS when in high performance mode in the BIOS, it will. 

 

In both versions when both cores are fully loaded, it will fluctuate from a 400MHZ clockspeed to 2.9-3.1GHZ or so and rinse repeat. While this is happening, the fans spin down once downclocked, only to spin back up to full speed when back to regular clocks. Apparently even with Intel DPTF, it lacks the smarts to adapt to unique thermal situations, by keeping the fans at high speed.

.. a non-hybrid vehicle with auto start/stop adapts when the user keeps on letting off the brake to edge forward 1 foot. It will stop shutting off the engine after every stop. But this laptop won't adapt. Oh well.

And we're back...

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