MOSFET Temperature concern

Rvenger

Elite Member <br> Super Moderator <br> Video Cards
Apr 6, 2004
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I know this may sound like a strange question. I have an MSI P67A-C43 and it does not have MOSFET heatsinks. I ran prime 95 and checked the MOSFETs with an infrared thermometer and some of them were around 52c/126f. When the computer is idle the temps are around 30-35c.

I have 2 concerns here...

Are these temperatures dangerous for MOSFETs?

I am currently overclocked to 4.3ghz with my i5-2500k with a 1.28v vcore, if I were to go anymore without increasing the CPU voltage, will I add more heat to the MOSFETs?



Thanks
Rob
 

Rvenger

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Yeah, I have mounting holes next to my mosfets and newegg sells some but I am wondering if I really need them.
 

996GT2

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Jun 23, 2005
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Side intake fan also helps if your case has a mounting hole for one.
 

Elixer

Lifer
May 7, 2002
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It really depends on the quality of the MOSFET that was used, so, you need to post the numbers from it.
 

PreferLinux

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Dec 29, 2010
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Most likely, that is fine. If you increase the CPU speed or voltage, you increase the power usage, therefore you increase the power dissipation of the VR MOSFETs, thus increasing the temperature.
 

Mark R

Diamond Member
Oct 9, 1999
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MOSFETs are usually rated for 175C / 350F.

You also can't sensibly heatsink them. The metal heatsink attachment is on the back of the MOSFET and is soldered to the mobo (which acts as a heatsink).

The exposed black plastic package is an insulator, so there is no point attaching a heatsink to this.

Best thing to do is just ensure reasonable sideways airflow over the MOSFET area.
 

Rvenger

Elite Member <br> Super Moderator <br> Video Cards
Apr 6, 2004
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The MOSFET says

NIKOS
P0603BD


There is smaller print that I cannot read on it.
 

WhoBeDaPlaya

Diamond Member
Sep 15, 2000
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Not close. 52C is cool for those VRM FETs.
The ones of my Biostar TA870+s run fine at 70+C (also no heatsink).
 

Rvenger

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Apr 6, 2004
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Not close. 52C is cool for those VRM FETs.
The ones of my Biostar TA870+s run fine at 70+C (also no heatsink).

I actually took the thermometer closer to the mosfet and it was 70+C... must be a typical temperature for these.
 

WhoBeDaPlaya

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Sep 15, 2000
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I actually took the thermometer closer to the mosfet and it was 70+C... must be a typical temperature for these.
This is under load right? That's the temp on mine (hottest ones - some of them run ~60C) when running Prime95 full bore (X3 740 BE @ X4 3.8GHz).
 

Rvenger

Elite Member <br> Super Moderator <br> Video Cards
Apr 6, 2004
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This is under load right? That's the temp on mine (hottest ones - some of them run ~60C) when running Prime95 full bore (X3 740 BE @ X4 3.8GHz).

Yes, full load Prime 95 Small FFT test
 

bryanl

Golden Member
Oct 15, 2006
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MOSFETs are typically rated for at least 125C maximum channel temperature. The main reason for heatsinking them may be to keep surrounding capacitors cool. While caps are rated for 105C, that's only for a few thousand hours, or much less than the lifespans of MOSFETs.