Dell XPS 13 9350 not using C-states

Hey all, I've had my 9350 for quite a while now, and it's always had poor battery life. However, this never really bothered me because most of the time, I'm plugged in. However, now I spend quite a bit of time running on battery power and now the 3-4 hour battery life just doing basic tasks like browsing and word processing is annoying me.

I've been using Throttlestop to undervolt since I got it, and after researching a bit, I checked my c-states to see if they were working. They aren't at all: https://imgur.com/a/aR4ZI

I checked my bios (v1.6.1) and c-states are enabled. Speedshift is enabled both in my bios and within Throttlestop. As past threads have suggested, I've updated my Intel iGPU driver, my bios (I was running 1.5.1 before and figured it couldn't hurt), and my Intel RST driver. I also reinstalled Windows once too a few months ago. What gives?

Any help would be appreciated.

 

Your ThrottleStop screenshot shows that your individual cores are using the C7 C State but the package C States are not working. When both cores enter C7, the entire CPU package should also be able to drop down to C7 or a deeper package C State for further power savings. Hopefully some other 9350 owners can run ThrottleStop to see if their Package C States are working or if they have been disabled by Dell. This happens. Some stability issues get blamed on the C States so some manufacturers just decide to disable them. 99.99% of consumers will never know the difference. You can contact Dell but they will probably tell you to stop running third party monitoring software because it is not supported, blah, blah, blah.

Just for the record, my wife's Lenovo laptop with a Core i7-7500U seems to have no problem using the deeper package C States such as package C8. Unfortunately, Package C9 and Package C10 are about as rare as finding bigfoot or a sasquatch on your lawn.

 

Search the throttlestop thread for some good tips.

Also, you should concentrate on core c states first. Get the c0% on the main page to just a few percent on idle; finding processes that are out of control pushing that c0% up will extend battery life. The throttlestop thread can help there.

Also, I have package c states running to C8 on my Dell XPS 9550. I needed to load up an intel driver to activate them; you can search my posts for ideas (particularly in the throttlestop thread). But note, uness you are idle or just doing light internet browsing, package c states benefits disappear. There are a lot of better ideas and more detail on that thread from people with laptops similar to yours.

 

Your post about installing the Intel SATA driver was one of the many drivers I attempted to install. Unfortunately that did not work.

 

I went back into the bios and unchecked both speedstep and c-states, and my package c-state limit got changed to c1. Other than that nothing changed. So my bios IS controlling it to a degree.

 

Try updating your DPTF drivers to the latest.