Vostro 5401 slow on battery

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Hello Dell Cares,

Instead of always giving your canned replies why dont you provide some solutions to your customers instead of the customers helping other customers.

Your dell support is lousy it does not even exist.

Hi There,

As per the diagnosis, we've identified that the system hardware is working fine. For the issue to be resolved, as we have limited support for Ubuntu Operating system, you may check on the open source platform

https://dell.to/2J2KNP3

Hardware does not give errors - but it works terrible. When disconnecting the battery it works OK almost until 70-75% of capacity and then dramatically slows down. No overheat or errors - but it becomes unsable, like I do not have 10Gen anymore but returned to the era of Pentium II.  Even if I reboot , even reboot different OS - no matter Windows, pre-installed Ubuntu or some live-usb - it continues to run slow. Until I plug the cable in. Or - charge battery almost to 100%. 

As I do not have any error message - it does not overheat, does not report any issue - seems that it is a feature that Dell implemented intentionally. And it is not in OS - I boot several OS's with the same results. SO it is either hardware or BIOS (my BIOS is latest) - and for me it makes absolutely unusable as I use laptop most on battery.   I still hope for some fixes in BIOS but looks like i need new PC.

Looks like it is not a feature but a bug. FInally i set up several runs on Ubintu with Unigine tropics benchmark loading GPU. The test run was simple - charge 100%, run benchmark, unplug power.

Then the rhings go weird. Up to 75% of battery it runs full speed as set by ubuntu. But on 75% speed drops about 4 times, CPU get 400-500Mhz, Gpu 150-300 ( even below the minimum 300 set by OS). Barely moving. And this goes till 45% of battery when - unbelievable - the speed returns back, CPU and GPU come to the normal frequencies and things continue fine. Maybe there are some more magical numbers back and forth but after 40% I plugged the power in, charged to 100% and the cycle of 75-45 was repeated again.

So hopefully in the next releases of BIOS this buggy 75-45 region will be fixed

Hi There,

Have you tried to flash previous version of the BIOS and checked if that makes any difference?

Hello. We are waiting for your revert. Do write to us at your convenience for further assistance, until then we shall archive the case.

I can confirm this is still an issue with the latest BIOS v1.16.0.

I unplugged both the main and CMOS batteries for a bit and it seems to be working fine now. No more throttling between 75% and 45% battery.

The throttling issues are back after a full charge cycle. This probably needs to be fixed in a BIOS revision.

Any update? This is still an issue on BIOS version 1.18.0.

After conversation with support, new bios will be available in January

I tested one option. I set to use only NVIDIA graphics to use on desktop and then not slowing down. it look like bad managment intel graphics by BIOS. When i set default option then again slowing down. I tested this on Ubuntu 22.04

Thank you for looking into a workaround. Some configs, like mine, don't come with dedicated graphics though. Hopefully the next BIOS release will fix this.

Hi @thehuberts, BIOS v1.21.0 did not fix the issue unfortunately.