poor contact between VRM and heat sink

[Mtt]

When the VRM on my motherboard gets hot, it starts throttling the CPU. I added a fan blowing to the heatsink on the VRM. It helped a little. But when I add more voltage to the CPU, it started throttling again. When I touched the heat sink, it is not even warm. I guess the heat sink was about 25 celsius. So I think heat is not transfering well to the heat sink.

Is there anything I can do to fix this? Is there some kind of paste or TIM that I can use? How hard is it to apply these stuff?

 

[BrightCandle]

In my experience the VRMs are typically attached to the heatsink with quite a thick heat pad. This allows quite a loose fitting heatsink to be used over the top of the VRMs. In practice VRMs don't output a lot of heat, they don't often get very hot. I have had one machine in the past that had a similar issue and I watercooled them, but presumably you aren't starving the VRM heatsink of air flow with a water setup for your CPU since its cool anyway.

It could just be there isn't a good contact, should be easy enough to check. But the heatpad used is usually more than good enough to keeping the VRMs cool enough. You could try applying a bit of TIM on the top of them as well so they contact better with the heatpad, but really the heatsink is probably cool just because there isn't much energy being dumped into the heatsink. That just means there is a large temperature difference from the VRM to the heatsink so you need to improve the interface, some TIM might very well be all you need to bridge the potential gap.

 

[Turtle.Man]

+1

I use 3M thermal tape for this purpose. It will give you good contact between the VRM's and the block/sink.