Hi Alan,

I have been troubleshooting poor performance on an XPS 9570 without much luck the past 2 weeks. Drops of up to 80% performance in games (from 150fps to 15-30fps) V-sync does not fix the issue, makes it worse. Terrible performance with Adobe video editing applications. 

To answer your questions:

a) Yes exact same games, same Adobe applications.

b) AC power

c) Updated to windows 1803  (I believe this is could be the problem!) :Hmm:

d) Updated to BIOS 1.3.1 for XPS 9570 (again possibly the problem!) :Hmm:

e) Yes, I've tweaked everything to maximum and set all apps to use Nvidia GPU.

f) No faults detected. I tested with the recovery image and then updates (from Dell site) no change.

Also

I wiped the laptop back to the factory image from the recovery partition. This didn't fix anything... even with the old drivers. It was working fine when I first received the laptop, had no performance problems. The fact this is no longer the case with the original factory image is puzzling! I suspect the recent BIOS update is the issue.

Other issues include, videos stuttering for the first few seconds or when the cursor is moved. Videos not up-scaling correctly on YouTube (You can see a pixel-like grid on 1080p and lower) When you move the cursor in full screen videos appear smoother and up-scaled. When the cursor and play-bar dissapears videos lag for a few seconds and you can then see a grid/rough edges as the videos aren't up-scaling.  

Lastly both the Intel and Nvidia GPU are under load at the exact same time under the performance monitor. The GPU switching might be broken, causing all these issues. I re-installed the Intel Thermal Dynamic Platform driver and even rolled it back, but had no luck.

For the laptop to suddenly drop in performance by 5x is beyond thermal throttling. The only other explanation I can think of is a hardware fault if not the BIOS or Windows update. A number of people have reported these faults over the past few weeks.

Please send this to the system engineers/software devs so we can get this fixed ASAP!