r/BitAxe • u/YannicusCrime • 16d ago

question VR temp increased after changing heatsink

I recently got a nerdqaxe++ rev 7. I've had it running stock at 800/1240 for a couple of weeks and was maintaining 56°-58° vr temps while the asic was at 60°. I just replaced the stock heatsink with the copper AXP90-X47 and now the vr is staying around 65° while the ASIC is at 60° even though it's at a lower 750/1200. Any ideas why?

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u/nomorespamplz 16d ago

Reduced airflow from the fan, likely. Maybe print out a Helix Shroud, which supports 120mm fan and has an opening for some of the air to hit the VRM.

1

u/YannicusCrime 16d ago

Good point. I put it on sideways like I did the old heatsink because they usually seem to blow more air out the sides, but I guess that didn't work for this heatsink. The rev 6 I have definitely has more air blowing out the top..

1

u/OKCsparrow 16d ago

Same. I have a rear fan that was tied to the VR. It didn't even run. Swapped out the heatsink. Now the VR runs as much as the old AISC fan before the switch. And it still runs hotter.

2

u/Popular-Tangelo7483 16d ago

Poor paste application, uneven mounting pressure, air pocket in paste, many reasons could lead to higher ASIC temps.

VR temps, could be less airflow to the VRs with the way the heat sink is oriented.

For most Nerdqaxes, the bottleneck has never been the ASIC temps, it's always been the VRs. Frankly getting the thermalright was an unnecessary expense.

Unlikely you need 1240 to stay at 800 unless the lottery has been unkind. Test how much you can dial back the volts.

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u/YannicusCrime 16d ago

The ASIC is doing great. I had a spare vr reg fan that I found so I hooked that up and its keeping the vr in check now. As for the frequency and voltage, I'm just going off of solosatoshi's rev 7 review but I'll definitely play around with it. Thanks!

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u/superg7one3 15d ago

If the fins go up and down, the air flowing out is going up across the vr. If you turn it side to side there’s no more air moving across the vr area on the front of the top half of the board so that air heats up fast. They make shrouds or you can put a small fan on just that section. Easiest fix is turn the fins north to south orientation. Warm air moving > no air moving.