Bootlooping after replacing stock Intel CPU cooler

[ss88]

Dell XPS 8930
- Intel Core i7-8700 @ 3.20GHz
- 32GB RAM
- NVME SSD
- 2 Nvidia Quadro cards

The stock cooler runs so loud that it's not practical to use under significant load. So I replaced it with the Arctic Freezer 11 LP Intel Low Profile Cooler. Cleaned off the CPU with a little isopropyl alcohol, blew it off with a dryer (on no-heat setting), installed cooler which ships with MX-4 thermal paste.

• On first boot, PC starts bootlooping without getting to Windows login screen (or even showing the wallpaper) before it starts the next bootloop. I visually confirmed both CPU and case fan are running.
• I powered down, and unplugged all DP cables except one. Power on and bootlooping commences.
• after a few loops, Windows recovery launched and I was able to load in Safe Mode. Tried restarting and it went back to bootlooping.
• Dell Support Assist auto launched during one of these loops and performed system scan and no issues reported: "Hardware scan complete with no issues"
• still bootlooping
• when Windows recovery auto launched, I selected Startup Repair option, and it's been fine since. Plugged all my monitors back in and seems to be fine.

CPU runs cooler (and quieter) with the new heatsink + fan assembly, so it's not an overheat situation. Any ideas on what happened that fit with the fact pattern described?

I have a backup image of the OS. Should I restore the backup, or just be happy as long as the PC behaves?

 

[Nobu]

Check the capacitors near the socket. Some heatsinks are too big, and will sit on those caps. When they're secured, they exert uneven force on the socket, and may cause the pins in the socket to be misaligned or lose contact. May even damage the caps if the pressure is high enough or one is already weak.

 

[pendragon1]

yup. these stupid ones that are in the normal "keep out zone"...

 

[ss88]

Nobu pendragon1 thank you both. I'd have never guessed it.

The PC was running normally today, but after you mentioned the caps, I went back and looked.

It's close, but there is clearance, as verified by sliding a piece of receipt paper (very thin) between the caps and the heatsink.

However, on the top side, the copper pipe was actually touching the centermost cap:

I had tightened the fan onto the heatsink pretty firmly. I backed out those screws just a little bit and that was enough to allow a piece of receipt paper to slide between the cap and the pipe.

Booted up just fine. Thanks again.

 

[pendragon1]

Nobu pendragon1 thank you both. I'd have never guessed it.

The PC was running normally today, but after you mentioned the caps, I went back and looked.

It's close, but there is clearance, as verified by sliding a piece of receipt paper (very thin) between the caps and the heatsink.
View attachment 452604

However, on the top side, the copper pipe was actually touching the centermost cap:
View attachment 452605

I had tightened the fan onto the heatsink pretty firmly. I backed out those screws just a little bit and that was enough to allow a piece of receipt paper to slide between the cap and the pipe.

Booted up just fine. Thanks again.

nice. notice that white square all around the cpu area on the pcb? thats the keep out zone, oems like to break that on their custom boards all the time.