VRM / Fan Advice

burninatortech4

Senior member
Jan 29, 2014
486
189
116
Context: Running a Ryzen 7 1700 at 3.8ghz 1.375v with the Gigabyte AB350M-Gaming 3.

My VRM temps routinely peak 80C running BOINC and sometimes during gaming. I have great airflow in my case [Define Mini C TG] with 4x 140mm intakes through a H110i and a 120mm exhaust. I've been told to get a 40mm/50mm fan and anchor it to the VRM with zip ties to solve the temperature issue but I can't picture in my mind how to do that.

Does anyone have any experience mounting fans on B350 VRM's?



 

VirtualLarry

No Lifer
Aug 25, 2001
53,758
8,008
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Are they heatsinked? I have the same board, purchased it to drop in some Ryzen APUs, but I'm too lazy to dig it out and look at it.
 

mindless1

Diamond Member
Aug 11, 2001
7,092
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What materials and skills do you have? In some cases (pun intended) I've made a fan bracket out of sheet aluminum, maybe 0.06" thick, then screwed that to the rear wall of the case, drilling holes in the case if needed. In other cases you might be able to get away with epoxying a magnet to the bracket, assuming steel case wall to attract it.

In some cases I have epoxied brass motherboard standoffs into heatsink fins then used long 4-40 screws to mount a fan. In some cases I have drilled tiny holes through the sides of two or more heatsink fins then used thin, solid, uninsulated (or only enameled) electrical wire to strap a fan on.

I looked at a few pics of that board but they seem to have excessive contrast to the point where it's not clear to me exactly how that heatsink is designed. It looks like it has either a solid top plate or at least fins that bend at a right angle, or some kind of ill conceived clip on piece that only serves to be fancy and show the manufacturer name (I hate those).

Anyway that makes me suspect that strapping a fan on top will not be as effective as putting one on the side yet that complicates the mounting. What kind of heatsink are you using? If it's a heatpipe style with an open area towards the bottom that a fan could pull air through, you might be able to mount the fan on that and have it close enough to push some air through the VRM sink fins. Then again the picture I saw of the mATX version of that board, made the heatsink look like there is minimal fin area on that side of it and the airflow would be more effective from the other side or running the length of it.

Otherwise, depending on your fabrication skills, a metal plate affixed to the rear case wall could come out at the area where the RJ45/USB/audio jacks are, make a '90 turn and position the fan down near the board pointing upwards to blow through the 'sink fins length-wise, though putting the fan on that long a bracket could introduce excessive vibrations if it's not a very well balanced fan and/or you mount either it or the bracket itself with dampening material, foam or rubber, etc not a hard mount.

If the heatsink uses standard form factor and mounting holes (though it looks like it might be machined to fit around some capacitor(s)?) then you could swap in a different heatsink to allow top mounting a fan.

How is the thermal junction between the 'fets and heatsink achieved? If tape or a sil-pad, you might have better conduction using thermal epoxy or (thick) heatsink grease. It might also help if you lapped the bottom of the heatsink, and going one step further, took some sandpaper and wrapped it around the sink, then used that to lap the 'fets so they too are as perfectly flush as possible. If the interface conduction was bad originally, this might be enough and you don't need a fan immediately adjacent to the heatsink.

Of course some of these things will void the warranty.
 
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burninatortech4

Senior member
Jan 29, 2014
486
189
116
Are they heatsinked? I have the same board, purchased it to drop in some Ryzen APUs, but I'm too lazy to dig it out and look at it.
Yes it's heatsinked. Here are some pic's of the heatsink from a video I found on youtube.

https://imgur.com/a/vRexV

What materials and skills do you have? In some cases (pun intended) I've made a fan bracket out of sheet aluminum, maybe 0.06" thick, then screwed that to the rear wall of the case, drilling holes in the case if needed. In other cases you might be able to get away with epoxying a magnet to the bracket, assuming steel case wall to attract it...
I've been thinking about pulling the heatsink off the get a closer look at the pads/compound underneath. Didn't get it it this weekend.

My current plan is to rig one point down from the top to blow through the pattern of the heatsink. Not sure how I'll accomplish that with zip ties but I'll make it happen.
 

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