Are VRM heatsinks necessary if not overclocking?

[ironk]

Is it ok to buy a motherboard without VRM heatsinks if I don't overclock? Or is it better to have those heatsinks anyways for gaming? This is for a Asus M5Axx AM3+ Amd motherboard.

 

[Burpo]

Try it and see, but generally heat sinks are needed..

 

[ironk]

ok...but why do they make motherboards without the VRM heatsinks?

 

[Mark R]

It depends on the design of the VRM.

Most VRMs are designed so that the heat-tabs of the MOSFETs are soldered to the motherboard. The motherboard, itself, forms the heatsink for the VRM. The top surface of the MOSFETs is insulated, so very little heat flows up. However, a lot of a manufacturers still add heatsinks for decoration purposes.

Some modern VRMs are now designed so that the heat-tabs of the MOSFETS are on the top surface - these are mainly used in GPUs and laptops. On these, the heatsink is essential, as these VRMs do not use the motherboard as a heatsink.

 

[ironk]

thanks for explaining. How do I find out what type of VRM is being used? I don't know if the manufacturer support will know.

 

[master_shake_]

thanks for explaining. How do I find out what type of VRM is being used? I don't know if the manufacturer support will know.

the vrm is always being used.

it's converting 12volts in to 1.2-1.5 volts.

the reason for heat sinks on them is to have a more stable overclock without the possibilty of failure.

 

[WhoBeDaPlaya]

thanks for explaining. How do I find out what type of VRM is being used? I don't know if the manufacturer support will know.

Look up the part # stenciled on the VRM package.
Post a link here if you're not an EE and can't decipher the gibberish

 

[ironk]

alright, haven't purchased the motherboard yet but will look later. It is odd that they would put out motherboards without the heatsinks if the heatsinks are necessary.

 

[Mark R]

You can often tell by looking - you'll need to remove the heatsink to examine the MOSFETs.

If they have a big metal tab soldered to the motherboard, then they will be mainly cooled by the motherboard.

See last picture on this page: Link

If there is no large tab, then the heatsink may be a source of cooling: Link - note in this case there is a hidden heat tab underneath the MOSFET, but the MOSFET is designed for partial top-cooling.

For a more modern design, check out the Asus Rampage 3 in the link: Scroll down to find the Asus rampage 3. Note how the top of the MOSFETs are metal - these special MOSFETs have a heat pad on the top for enhanced cooling.

 

[ironk]

Thanks for the links and pictures. Wow, its a little confusing, but I did find a picture of it:

http://i.imgur.com/BRbwkcM.png

This from M5A97LE 2.0, what do you think? Its difficult to tell what is underneath since I don't have the mobo yet.

 

[Mark R]

That type is mostly (90-95%) heatsinked to the board. A top heatsink would only add a few %.

 

[ironk]

so you think its ok to use if I don't overclock? There will be gaming, so I don't know how hot it will get.