H370M-ITX/ac + i7-8700nonK = VR thermal throttling

[patrololo]

I've recently made my first build:
H370M-ITX / ac
i7-8700nonK
thermaltake V1 case
Cryorig M9i
2x8 G.Skill Ripjaws V 3000
1050Ti

I've got a problem with CPU throttling. When 8700 power draw is over 140W for few seconds throttling occurs. XTU says it's throttling due to VRM thermals. So I've set cpu offset -0.1V it stable, power draw is lower, but still during stress test or encoding, it's over 140W. IMO, V1 case has not a bad airflow (intake: 1x200mm and out: 2x80mm). Heatsink during throttling on vrm is hot, but not burning hot. Blowing another fan on vrm section helps but not much. Is there anyway to overcome this?

Here

https://www.tweaktown.com/reviews/8587/asrock-h370m-itx-ac-intel-h370-motherboard-review/index.html

test setup had a i5-8400 and author did not mention about any problems. In fact he said:

The H370M-ITX / AC's VRM is very good and will handle any CPU in a mini-ITX system.

But I believe 8400 has considerable lower power draw, so he didn't notice any problems. Please comment and give me some advices.

CPU temp during stress test (AIDA64 CPU+FPU) is around 88C.
Maybe bigger cooler eg. Cryorig H7 + delid, would lower temp that is given from CPU into motherboard (and into VRMs that are close to cpu socket). What you think?

 

[SkyNetRising]

Custom VRM cooling perhaps?
Or you can lower max turbo boost settings in BIOS.

 

[patrololo]

Full turbo is a goal. I was trying to blow cold air with fan from my hand, but it didnt help neither.
And there is not much space 🙁

 

[patrololo]

I thinking about some custom heatsink. Maybe it would do the job. Something like this for example. Has anyone heard or seen custom vrm's heatsinks?