... when my XPS 7590 is plugged in, it gets throttled down to 0.78Ghz. The only way to remove the throttle is to unplug the PC, at which point it immediately clocks up. Additionally, the power adapter plug is now very flaky and often doesn't charge the battery. You have to move it around, rotate it, bend the cable, etc. until a tenuous connection is formed.  Some additional notes: I added the boldface. Those issues are all connected. The AC adapter is faulty. It's possible that there is also a DC jack issue, but at this point it seems likely that it is the AC adapter causing all these issues. Try with another genuine Dell adapter of the required wattage.  
Hi, I have a very frustrating issue where often when my XPS 7590 is plugged in, it gets throttled down to 0.78Ghz. The only way to remove the throttle is to unplug the PC, at which point it immediately clocks up. This started as an occasional issue and is now almost constant. The problem has been getting worse over recent weeks. It has made what was once a good laptop into a nearly useless and very expensive paperweight. This is not a power plan settings issue. Additionally, the power adapter plug is now very flaky and often doesn't charge the battery. You have to move it around, rotate it, bend the cable, etc. until a tenuous connection is formed. At which point, shortly after the laptop will get throttled down to 0.78GHz! Like the throttling issue, this has been getting much worse over recent weeks. Some additional notes: I am very disappointed and frustrated with this issue as I expected much higher quality from such an expensive laptop. Any pointers on solving this would be much appreciated.
XPS 7590 throttled to 0.78GHz