XPS 15 9550 suddenly became incredibly slow in all regards
What's the problem?
CPU seems quite slower than usual. Slow boot time, much slower application start time, OS and application animations are slower, all aspects of the operating system and applications are much less responsive, web pages load slower.
Examples of the lag:
(1) Just holding down the left cursor key in this text book to scroll left takes noticeably longer. Typically the cursor key would scroll to the left over each character smoothly. Now the cursor will lag over characters or jump over complete works as if I was doing it over a slow remote connection.
(2) Copying and pasting the "computer specs" below from the clipboard took about 4 seconds.
(3) The cursor cannot keep up with my typing aka I can't see what I'm typing until I stop and eventually the cursor catches. Using Chrome to type is excruciatingly slow.
Are there other process utilizing a high pct of the CPU?
No. As I'm typing this System Idle Process is 70%, Chrome.exe is 18-25%. WmiPrvSE.exe 1-5% everything else is negligible.
Have you installed anything new recently?
Yeah. Upgraded the Dell XPS 15 9550 bios from 1.11.2 to 1.12.0 per the Dell urgent update notification. I've since downgraded back to the prior bios version. Problem persists.
Did you try the Dell pre boot diagnostic (ePSA), SupportAssist, and Windows diagnostic tools at boot?
Yes. Everything checks out ok across the board.
Are all your drivers up to date?
Did you try System Restore?
Yes, I rolled it back to earliest available date on Nov-18. No effect.
Re: XPS 15 9550 suddenly became incredibly slow in all regards
If the CPU is stuck near 0.8 GHz, try disconnecting the battery for a while.
On some rare occasions, my 9550 wakes up from sleep slow, HWinfo64 showing "On-demand clock modulation" 50% instead of 100%. I can fix that easily by running ThrottleStop, maybe there are other ways (like changing power profiles or their settings).