Laptop not stable unplugged - even with stock settings

[4evrplan]

I bought a refurbished Latitude 5491 with an i5-8400h, and I've been learning to use ThrottleStop. I've had really good results with it plugged in, but unplugged, running TS Bench almost immediately causes the laptop to shut down. Prime 95 - shut down. I can't remember if I tried Furmark with it unplugged though. This is with completely stock settings. I tried setting MMIO to locked under TPL and under FIVR, I set the turbo ratio limits to 26 (stock is 42), and it still turns itself off when I run the benchmark. I'm not really sure where to go from here. Any advice?

 

[unclewebb]

Batteries in many laptops are designed for light internet use so you can check your email and maybe watch a video. Full load testing with Prime95, Furmark or the TS Bench can be overkill when not plugged in. If you are using ThrottleStop to prevent throttling, if the power demand is greater than what the battery can supply, your laptop has no other choice but to shut down.

refurbished

That might mean anything. Did someone clean off the screen and keyboard so it looks nice or was the battery replaced with a brand new Dell OEM battery? Many replacement batteries for laptops are junk.

Be happy that your Dell Latitude runs well when plugged in. Many of the Dell Latitude laptops with Intel 8th and 9th Gen CPUs have some horrible power limit throttling problems that cannot be easily solved.

 

[4evrplan]

Batteries in many laptops...

Okay. This laptop will be for my kid's school. I've already instructed them not to use it for anything demanding unless it's plugged in. I'm wondering if I should use some less intensive "benchmark" to dial in the TS settings while it's unplugged? Maybe I could just run pings in the background and refresh Gmail a few times? Would that be enough?

4evrplan said:
refurbished

That might mean anything.

Unfortunately, I don't know what all they did. I re-pasted it myself, and I know they didn't do that, because the existing paste was really dried up. But, at least the fan and fin stack were clean, so I'm pretty sure they at least did that. I was hoping they replaced the battery. On a full charge, it estimates over 12 hours of runtime, but I have not tested the actual runtime. While I had it open, I took the battery out and examined it to see if it had a manufacturing date. It did not.

Be happy that your Dell Latitude runs well when plugged in. Many of the Dell Latitude laptops with Intel 8th and 9th Gen CPUs have some horrible power limit throttling problems that cannot be easily solved.

I think mine actually is one of the models that historically had that issue. I don't know if I just got lucky or if Dell fixed it in BIOS or what. I flashed the latest BIOS firmware from August 18. 2024, but then I used these instructions from GitHub to unlock undervolting. I locked MMIO, and I was able to do -144mv on CPU and cache (I backed it off a hair to -139mv) and -200mv on Intel GPU and iGPU Unslice (backed off to -192mv because I was still seeing just the tiniest traces of graphical glitches in Furmark). I also changed the turbo ratio limits to 30, and it can run TS Bench and Furmark simultaneously for over 20 minutes without glitching or thermal throttling.

Thank you for your help and for this amazing tool that helps our computers run so much better!