Grasping at straws, 5820k is running too hot all the time (non OC)

[InconspicuousCustard]

I've had this ongoing battle with my 5820k and it's temperatures at stock clock, idling at around 42°C (107°F), which for me, is far too hot at around 2%-5% utilisation. The temps seem too high, as it is on a H100i GTX which should be giving me cooler temperatures than it is. At the moment, my pc is sat in a 21°C (70°F) room and it's temperatures are at 42°C (107°F) @ 3%, so my pc is twice as hot as the room that it's sat in. I was really hoping to overclock but it's not looking likely with these temps.

Running a stress test, it reaches 86°C (186°F) after about 20 seconds, so I aborted the stress test.

Stuff I've tried:

- Pump speed set to max
- Changed fans back to the stock fans (better but not a lot)
- Cooler is plugged into a molex, rather than a fan header
- Changed thermal paste multiple times, using arctic silver 5, using various methods.
- I changed my thermal paste yesterday, pea method, arctic silver 5, temps were around 35°C (95°F) in a 25°C (77°F) room, so only 10°C (18°F) hotter, which seemed about right and I thought I had finally solved my issue. I go to sleep and turn my computer on this morning and it's running a lot hotter in a cooler room. I have no idea what the issue is. I'm beginning to think that the cooler could be broken, but that probably isn't the case. Chances are it's something glaringly obvious and I've not spotted it.

If anyone has any idea of how to help me, please do so. Thank you

PCPartPicker part list: https://uk.pcpartpicker.com/list/VH4gHN
Price breakdown by merchant: https://uk.pcpartpicker.com/list/VH4gHN/by_merchant/

CPU: Intel Core i7-5820K 3.3GHz 6-Core Processor (£378.85 @ More Computers)
CPU Cooler: Corsair H100i v2 70.7 CFM Liquid CPU Cooler (£95.94 @ Ebuyer)
Motherboard: Asus X99-PRO ATX LGA2011-3 Motherboard
Memory: Kingston HyperX Fury Black 64GB (8 x 8GB) DDR4-2133 Memory
Storage: Samsung 850 EVO-Series 500GB 2.5" Solid State Drive (£135.54 @ Aria PC)
Storage: Seagate Desktop HDD 4TB 3.5" 5900RPM Internal Hard Drive (£106.80 @ Aria PC)
Video Card: EVGA GeForce GTX 980 Ti 6GB Superclocked+ ACX 2.0+ Video Card
Case: NZXT S340 Elite (Black) ATX Mid Tower Case (£74.97 @ Amazon UK)
Power Supply: Corsair RM 1000W 80+ Gold Certified Fully-Modular ATX Power Supply
Operating System: Microsoft Windows 10 Home OEM 64-bit
Total: £792.10
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-04-10 13:15 BST+0100

 

[Atomicdonut17]

After doing a bit of research on that particular cooler, several people report a fail of the pump after just a few months, with mostly positive results throughout. However, you could be the 1-in-a-million. If it's not a pump failure, then you may want to use a different fluid solution. Some people go as far as using AntiFreeze in their coolers!

If this doesn't work, try to test out another water cooler, air cooler or even the stock cooler to compare results. At non-OC, a stock or aftermarket cooler will be just fine until you come up with a better solution.