XPS 13 (2015) i7 CPU Speed (again)

Did you set both plugged in and on battery to 2.9GHz?

are u sure the speed is limited, or is it just slowing itself down for a while?

After a bit more testing, the processor limiting appears to happen only when the computer is put into sleep mode when plugged in.  If I sleep the computer while on battery and the resume, it does not exhibit this behavior.  

It's 100% repeatable on my machine, at the very least.

Yeah, it is definitely capped at 0.48.  It says the maximum speed is 2.39 GHz, but it will not go about 0.48 Ghz or above 20% utilization.

I have both plugged in and unplugged set to 15.0W @ 2.4 GHz.

If I plug it in and then immediately unplug it, things work as expected and it will go to 100% utilization.  It's only when the computer comes out of sleep mode.

I believe I have fully figured out the problem.  I am connecting the computer through the Dell Power Companion PW7015M.   The computer sees the PW7015M as a 35W adapter (I got the warning message after flashing BIOS A01).  

If I do not use the Dell Power Companion, everything works great and the processor performs as expected at all times.

With the Dell Power Companion connected, if I sleep the computer when it is plugged in, and then resume it on battery, the computer will limit itself to 0.48 GHz, and 20% utilization.  This can be remedied by plugging the computer back in.

I can reproduce this behavior 100% of the time and I'm wondering if others with the Dell Power Companion are seeing the same issue.  At the moment, I would consider this a minor annoyance since now I fully understand what is causing the issue, but in general, it seems like this should not be happening.

Yes look at maximum power state as well. Dell probably tweaked a ton of setting to squeeze out their battery numbers.

same problem with i5 version ,cpu caps on 0.77 in performance mod ,0.57 in power saving mode and some times even a restart will not solve it .the new xps is not reliable ,i'm learning programing and i need a reliable laptop ,i'm really disapointed on new xps 13 ,macbooks  are much better in reliability .

I have tried setting the minimum processor state when on battery in the advanced settings to 100% ,but it didn't solve the problem.

Just to be 100% clear, this problem ONLY occurs for me with the Dell Power Companion.  I initially thought this was a much more severe problem.

I would suspect this is a BIOS issue, or it's possible I have a bad Power Companion. (I might ask for a replacement power companion).

In any event, this is the only issue I have encountered with this machine and it's kind of an obscure one since it involves the Power Companion.  I wonder if other people using external batteries (not necessarily the Dell one) that run at a reduced wattage will see the same issue.

The easy fix is to just unplug the machine before I close the lid if I'm on the road.  Hopefully there will be a better fix in the future.

XPS 13 is very reliable, there are just a few settings that need to be corrected. All of these issues can be fixed, either by BIOS or by the user. It's a matter of us trying to resolve the issue first, and if we can't on our end then Dell will look into it on their end to try and fix it.

So I had the same exact issue. To resolve it I unplug everything and then put the laptop to sleep (close lid) and then open it in about 5-10 seconds - CPU jumps back to normal. I checked all of the settings and for me it happens in both High Performance and Balanced. I haven't really used Power Saver yet. 

Interesting problem!

Have you tried all the USB sockets?

Are you using the USB cables supplied by Dell? There are two classes of USB cables with respect to power delivery; the difference is 26 vs. 28 guage wire. You need the higher capacity. With my Asus t100 tablet, the “normal“ 28 guage cables WILL NOT charge the tablet, not delivering the needed wattage. A laptop will need more than the tablet. Even if using the Dell cables, I would get a high capacity cable. With. not  enough power supplied, portables cannot run the unit and charge the battery at the same time, or will not allow maximum CPU speed.

This has nothing to do with USB cables.  Perhaps you're responding to the wrong thread.

My XPS 13 gets stuck at 0.77-0.79 GHz when I boot it up by opening the lid, or with the power button on the right. However, I made this strange discovery that will work in the proper CPU range of 2.5+ GHz when I put the machine to sleep, then awaken it by clicking on the touchpad instead. It's bizarre.

I have been able to reproduce the exact same problem with the Dell Power Companion. I am running Linux so thought the problem might be related to something in my Linux config, but after narrowing it down to the Dell Power Companion (and not the wall charger), I think that the problem is exactly the same as you described. Definitely some kind of either BIOS or hardware problem.

Anyone have a suggestion on how to fix it?

Same problem here. Latitude E5540 running Windows 7 and Dell Power Companion. It seems to me that if Dell made this power supply and it doesn't work with their own machines, there is something seriously wrong. Did they even test it? Any help is greatly appreciated!