VRM Temperatures, with / without extra Fan - findings

WanaGo

New Member
Hello,

I have a bit of a weird setup going on, making a PC for my son out of parts I had and upgraded from, and found something very interesting when doing some stability testing with Cinebench R23.
Its just sitting on the bench, not in a case at this stage.

The system is based around my Ryzen 9 5950X. Originally the plan was to use it with my Crosshair VIII Hero, however it turns out the motherboard is faulty (the reason I upgraded but couldnt figure out exactly what component was faulty at the time). So I got a cheap Gigabyte DS3H AC B550M motherboard, and currently using that in the test setup (to then go into my sons PC).

First run of Cinebench, it gets something in the region of 26000 points, but after doing a 10 minute test, it settles on the final score of about 19000. Originally the CPU was throttling as this has an air cooler on it (it was watercooled when I used it), and it was hitting 90C and so determined the CPU cooler wasnt up for the task of the 5950x. So I got a Deepcool AK620 cooler and put that on today, and its better, its getting to about 82C at the end of the Cinebench run, so I dont think its throttling anymore, however the scores did not increase much and still dropped.

I installed HW Info and had a look at temps, and it looks like the VRM's on this motherboard are getting into the 120 degrees C region, which is pretty darn toasty.
It has a basic heatsink on the 'rear' side of the CPU VRM's, but nothing along the top VRM's, and nothing on the chokes. So as a test I just put on some stick on heatsinks to ones that my IR gun said were getting the hottest, only did about 4 little heatsinks, but that didnt do much by itself, only a few degrees difference. I then got a small 50mm fan I had in a box, and just sat it on the bench pointing at the VRM's (from what would be the top of the motherboard, pointing under the CPU cooler), and low and behold, the temps are now in the 60's, and the Cinebench score finished on 24000.

VR Loop1 and VR Loop2 is what I am referring to, these were both in the 60's now, rather than 105C and 111C respectively.
The VSOC MOS peaked at 89C (and dropped into the 40's with the fan), and the VRM MOS peaked at 123C but did not really drop much even with the fan, was more 118/119C with the fan, so that sensor must be located somewhere else.
Unsure if that is a problem or not, but I assume the VR Loop1 or 2 are what is most important here...

But what a difference, I was not expecting the VRM's to cause things to throttle this much.
I guess this Motherboard really is not 'ideal' for the 5950X even though it works and is supported.
Hopefully when this is in the case, the top fans will provide enough air movement that this extra little fan is not required, but I guess we will find out soon enough.
 
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