Same here, inspiron 14 7000, i7 8th gen, 8gb, Nvidia MX150

Fps drop while charging, works just fine when on battery.

Already set high performance on both (charged or battery), 3D setting nvidia, update the latest bios, latest driver, but all didn't work

Hi guys,

I had this issue and resolved it after some painstaking digging and trial and error. I also have a Dell, with similar specs to what has been noted, however my processor is the i7 8550u. Unplugged my computer played games far better than when plugged in, particularly WoW. A drop of around 40 dps from being unplugged to plugged in. This issue i initially had thought was due to the AC adapter only being 65w, and perhaps needing a 90w adapter to provide enough power for the laptop to perform, as many others had mentioned with their HP laptops. Don't bother with this, it did nothing for me. I had also tried every other possible setting you can imagine (as mentioned above, updating BIOS, Nvidia settings, Power management settings).

The issue is in fact the CPU, and it doesn't actually matter that your cores aren't really overheating (at say 95C+), it's the fact that there is some thermal throttling going on even at 75C. I figured this out after downloading a simple CPU tool to look at core temp. When unplugged, the cores stayed at around 69-70C while gaming. Once plugged in, the temp immediately increased to 73-75C+, which is obvious given the wattage increase to the CPU. As soon as the heat reached 75 in any given core, issues came about. Now, to be sure, I actually lifted my laptop in the air while it was plugged in, and put it towards a fan for better ventilation, and sure enough, despite being plugged in the fps went back up 20fps, and the laptop stayed at around 72C. That was the light-bulb moment for me.

I would highly recommend you download ThrottleStop (hope I'm allowed to post that), which allows you to lower the power being consumed by undervolting, and take measures to control the heat of your CPU, without affecting performance. It completely fixed my issue, where my temp doesn't get above 70 while gaming, and fps is as high as can be. There's a simple walkthrough included with the download that will provide guidance. I really hope this helps some people because i was ready to throw in the towel.

I have the same exact specification inspiron as you and I have contacted Dell support over a year ago and no one was really able to solve my issue, I had tried everything as everyone had mention including a clean installation of windows but nothing seemed to work, this laptop has a pretty poor battery I have used the laptop for almost 3 years now and the laptops battery lost its ability hold its charge for longer than 10 minutes within my first year of usage.

I had my battery replaced and got a 90W charger aswell but as one of the reply has said the charger was not the issue and using it made no difference whatsoever also the battery that I got replaced also got to the same point within a year and a half after being super careful and trying to put as little strain on the battery as possible. 

In my case my fps drops are quite a bit worse as the fps drops are generally from 45-60 to 5-10 FPS.I have yet to replace my battery because I know it will die within a year and now I am just using it on charge and minimizing my gaming since its not really a pleasant experience playing on such low FPS.

I did undervolt the system but no improvent occured I hope someone is able to come up with a fix for this and I will try undervolting the system again to see if it helps though at this point I doubt anything will actually fix this issue.

Had the same issue for me as well. However, the configuration is different for me. I have i5-9300H and GTX 1060 and the issue was resolved after I increase the FPS settings for Nvidia whisper mode to 120. It also gets resolved when I disable the whisper mode entirely.

The issue is usually related to the poor thermal solution, keep the ventilation and fan clean and perhaps apply thermal paste on both CPU and GPU. 

My friend did a clean install that also solved his issue in case the issue is related to a software conflict.

This page may help you in finding a solution: https://gamespec.tech/fix-laptop-fps-drop-when-plugged-in/

Hi, my name is Vishnu Gopan G M, these settings can help you with this problem. you can use these settings at your own risks

Step 1:
Go to the Power option, Edit Power plan then click to open it.

Step 2:
Click on Change Advanced Power Settings

Step 3:
Expand Processor Power Management and then expand Maximum processor state

Step 4:
Change the Plugged In to 100%

Step 5:
Expand Multimedia Settings and then expand When playing Video

Step 8:
Then under Plugged In select Balanced

Step 9:
Click Apply and then click OK

Step 10:
Restart PC and verify

Here I provide a registry key link for these settings, you can enable or disable these settings by downloading the file (Use this when not on your PC or laptop)

https://www.mediafire.com/folder/jl6jh3dtvgfw8/Vishnu_Gopan_G_M 

Did you observe this issue after any recent Windows or BIOS update?

Are you using the Original AC adapter shipped with the computer?

Do you observe an FPS only the moment when you connect or disconnect the AC adapter or throughout the time the AC adapter is connected?

Please run a CPU & GPU stress test on the Dell Support Assist application & check if there is any FPS drops or thermal issues observed.

Same here on inspiron 1500.Fps drops suddenly while charging but goes well while unplugged.