12-29-2015 04:40 AM
I am having issues with the CPU speed dropping too low when running on battery power. This is grinding the machine to a halt to where i cannot even watch netflix on battery below 30%.
Plugged into the power cord the CPU core speed is 2694 and multiplier 27.
On battery above 30% CPU core speed is 1696 and multiplier is 17.
Battery below 30% the CPU core speed 498 and multiplier is 5.
I have entered into the power management settings and changed the minimum processor state but this has made no difference to the above values.
Im quite a novice when it comes to computers so please be kind.
02-03-2016 09:51 AM - edited 02-03-2016 10:07 AM
Un pure impulse I bought a Yoga 500-14IBD with the 3805U processor on sale as it was almost dirt cheap. Also missing my 900 which is for repair at the moment so hey the 500 is a perfect 2nd portable machine. Had I bought if before the 900 I'll probably never have got the 900.
For most parts it's a nice machine and I'm quite impressed how powerfull the CPU and graphics are at most common everyday tasks except heavy gaming but since I'm no gamer... Even handles multiple high res videos simultanios - just what my need is, consuming multimedia while surfing or working.
But.... This problem has nagged me too. Battery isn't the largest (it's the lower 30wh which only has two cells - the upper 500 versions has the 3 cell 45w version). Below 30% CPU everything grinds to a halt and have a video running is just about impossible unless a very low res and not doing anything else.
Searched the internet. Nothing on Lenovo machines. Only the way too common experience of only finding other people having the exact same issue but no solution. However I stumbled upon some having an A..s and one thing worked for him and I figured that's one thing I haven't tried - why on earth should it even be related to the issue:
----- T H E - S O L U T I O N -----
Enter BIOS setup. Enable virtualization - voila! Full CPU speed even below 30% battery left - NICE!
What's not as nice is that ideally virtualization for security reasons should be disabled unless you have a need to enable it (running virtual machines etc.). But hey more a theoretical risk than a real one.
CPU still seems to prefer lower speeds dropping faster (my impression) but now it's perfectly useable running FHD videos while browsing etc. and no problem peaking at the (task manager says) 1.88 GHz
Now I just wonder why... Makes no sense to me. Either you have an option of throttling CPU on low battery or not. Now combined with virtualization....
06-02-2016 01:57 PM
here is an important remark. This trick worked for me only after i have updated my BIOS from BDCN31WW to BDCN63WW and enabled virtualization!
Thank you for the hint.
07-11-2016 12:06 PM
I updated the bios and enabed Inter Virtual Technology, and the problem remained the same. CPU utilization drops to 20% when battery is less then 30%
07-26-2016 08:31 AM
In order for Lenovo to better understand the throttling being reported by customers on Yoga 500-14IBD and Yoga 500-15IBD systems, it would help the investigation into these customer reports if the following information could be provided:
10-12-2016 08:00 AM
I experience this exactly issue on my U41-70, I'll provide extra information when i'm next using my machine but it's rather an inconveniance. It renders the machine totally useless. I thought it was a software error and tried hunting down a setting but found none, I also tried the bios but found nothing to do with the issue.
The specs are as follows:
11-24-2016 03:56 AM
My model is Lenovo Yoga 500-14IBD with intel core i5.
Bios version: latest BDCN71WW
Power setting does not impact the problem. Is always as you have maximum performance, balanced or energy saving
These are the screenshots of the problem when battery is less than 30%, the only solution is using throttlestop and uncheck bdprochot.
The pc without throttlestop and with the battery less than 30% is useless. Also only open a web page is incredible slow.