VRM circuit cooling

[Herr_Koos]

Good day all,

I've been doing some reading regarding cooling of the VRM circuit (my mobo doesn't have any cooling in this area), and have decided to purchase some heatsinks. I would just like to confirm that all the components I have outlined here need to be cooled.

They get pretty hot to the touch when under load, I know that much for sure.

The board is an Asus M5A78L-M/USB3 with an FX6300.

Any suggestions and asvice would be welcome.

 

[junkeymonkey]

well if they get hot to you and you want to dress up your board with sinks then why not ? its all about your personal preference- only you can determine weather the out come of a project was worth it or not . if your happy and satisfied that all that matters in the end if not then you know better next time ..

look around -find something you like to try

example
http://www.frozencpu.com/cat/l3/g40/c16/s1859/list/p1/Air_Cooling-Chipset_HeatsinksCoolers-Mosfet_Chipsink-Page1.html

 

[JackNaylorPE]

If you have a "dead air" spot, I'd recommend one of these .... heat sinks will be ineffective w/o air circulation

http://www.newegg.com/Product/Product.aspx?Item=9SIA24G2U47409

 

[InvalidError]

They get pretty hot to the touch when under load, I know that much for sure.

Get an IR thermometer and qualify how hot "pretty hot" is on the packages.

Surface-mount power devices sink most of their heat into copper pours and layers in the motherboard. Their casing is made of epoxy or plastic which has very poor thermal conductivity. Even if you put heatsinks on them, 90% of the heat is still going to go out into the motherboard.

Also, most power semiconductors have 150-175C maximum junction temperature. They may get uncomfortably warm to the touch but are still internally well within their operating limits.

The most effective way of cooling small SMD chips is to cool the motherboard - their primary heatsink. In high power equipment, such as DC load testers and power supplies, it is quite common to couple surface mount power devices to the heatsink through the motherboard and tons of vias instead of putting heatsink directly on devices due to the package's high thermal resistance.

 

[junkeymonkey]

back in the ''good ol' days'' most board did not come with sinks and adding them was a thing to do , but now a days there so standard on boards there not as easy to find or a wide selection to choose from today

lot of nice ones that look pro are just long gone out of stock ..

them little fans do ok [active] my buddy has used them and claimed they did thee job ??

a good down draft cpu cooler that blows the air down on to and across the board may do the same for the vrm/mosfets ??

check out the fans on the last pic. [that thing should cool something ?? ]

http://www.frostytech.com/articleview.cfm?articleid=2076&page=3

 

[Herr_Koos]

They get pretty hot to the touch when under load, I know that much for sure.

Get an IR thermometer and qualify how hot "pretty hot" is on the packages.

Surface-mount power devices sink most of their heat into copper pours and layers in the motherboard. Their casing is made of epoxy or plastic which has very poor thermal conductivity. Even if you put heatsinks on them, 90% of the heat is still going to go out into the motherboard.

Also, most power semiconductors have 150-175C maximum junction temperature. They may get uncomfortably warm to the touch but are still internally well within their operating limits.

The most effective way of cooling small SMD chips is to cool the motherboard - their primary heatsink. In high power equipment, such as DC load testers and power supplies, it is quite common to couple surface mount power devices to the heatsink through the motherboard and tons of vias instead of putting heatsink directly on devices due to the package's high thermal resistance.

Makes sense, but then would you dispute the claims that VRM's without cooling could hold back the performance of a CPU, especially one with a high power draw?

 

[junkeymonkey]

hard to say if its all show and no go ?? all you can do is look up articles on how they may affect thermal throttling or not ?? I would guess any added heat adds to the collective and surely cant hurt any to try to cool ..

I'm sure you will see pro's and con's on that - where you stand now its pretty much a judgment call -- there not like 100 bucks to try and see

intel is not like AMD that gets overly hot anyway amd boards can get mean hot

looks like you can still get them vrm fans from asus store if they fit something you get to try ??

http://us.estore.asus.com/products/13g070385020


heres a link to something to read ?

http://www.overclockers.com/forums/showthread.php/657095-MOSFET-cooling-is-it-needed-for-oc-ing

 

[InvalidError]

Makes sense, but then would you dispute the claims that VRM's without cooling could hold back the performance of a CPU, especially one with a high power draw?

As I said, the VRM gets the bulk of its cooling from the motherboard. Heatsinks on top of plastic packages, just like DRAM, are mostly for show. Airflow across the PCB is more important than showy heatsinks.

Overclocking-oriented motherboards typically have eight or more phases for Vcore. If your CPU is drawing 100A overclocked (~150W), that's about 13A per phase and if the board uses 5mOhm FETs for switching, that's less than 2W per FET. Keep the PCB cool and the FETs will get all the cooling they need from it.

 

[Herr_Koos]

Thanks for the responses, everyone.

One point of concern was that the FET's get less airflow than before, since I replaced the stock AMD cooler with a TX3 Evo, which of course does not blow down onto the board.

So would it be best to point a fan straight at the VRM circuit on the board, or try and generate flow across it from the side?

 

[junkeymonkey]

page 8 last post from [alvinc5]

http://www.overclock.net/t/1202751/amd-fx-cpu-throttling-fixes-please-sticky/70

just get some aftermarket sinks and stick them on ?? pretty much coverd whats said here from us ??

nice job looks good with them here [also notice the down draft style cpu cooler used as well ]

http://cdn.overclock.net/9/90/90254953_vbattach100113.jpeg

 

[Herr_Koos]

page 8 last post from [alvinc5]

http://www.overclock.net/t/1202751/amd-fx-cpu-throttling-fixes-please-sticky/70

just get some aftermarket sinks and stick them on ?? pretty much coverd whats said here from us ??

nice job looks good with them here [also notice the down draft style cpu cooler used as well ]

http://cdn.overclock.net/9/90/90254953_vbattach100113.jpeg

See, I'm getting conflicting responses here. InvalidError maintains the heatsinks are ineffective and airflow on the PCB is the better way to go.

 

[junkeymonkey]

I did point that out a few posts above above .. ''I'm sure you will see pro's and con's on that - where you stand now its pretty much a judgment call '' and started out in my first post with ''personal preference's and experiences ''

you have to do what you fell is best and see how it works out for ''YOU''

 

[FALC0N]

VRM cooling is one reason I still prefer traditional top-down cpu heatsinks over tower designs. That downward airflow cools a range of motherboard components, including the VRM's, and it makes a big difference in their temps.

 

[GhislainG]

page 8 last post from [alvinc5]

http://www.overclock.net/t/1202751/amd-fx-cpu-throttling-fixes-please-sticky/70

just get some aftermarket sinks and stick them on ?? pretty much coverd whats said here from us ??

nice job looks good with them here [also notice the down draft style cpu cooler used as well ]

http://cdn.overclock.net/9/90/90254953_vbattach100113.jpeg

See, I'm getting conflicting responses here. InvalidError maintains the heatsinks are ineffective and airflow on the PCB is the better way to go.

You need both. Best is to add the heatsinks and ensure they get good airflow; since you replaced the stock cooler with one that doesn't blow down, then add a fan to keep the heatsinks cooled.

 

[junkeymonkey]

see ?? opinions are like butt holes , everyone got one [lol]

the darn sink kits are like only 20 bucks ? its not like you lost your lifes savings if it don't work out as you expected ?? just a shrug your shoulders thing and move on ??

 

[JackNaylorPE]

Makes sense, but then would you dispute the claims that VRM's without cooling could hold back the performance of a CPU, especially one with a high power draw?

Dispute what claim ? Based upon what measured data ? Here's a perfect example:

The power draw on some of the hi end AMD cards is such that CLC type cooling of the GPU is required. It is seen as "cool" by many, and I don't mean in a thermal sense, so vendors are now selling hybrid nVidia cards. To what purpose ? The fans on these cards don't even turn on till 65C and running full tilt overclocked to the max, they are running in low 70s. The 980 / 980 Ti don't throttle until they hit 85C so what is the point of lowering GPU temps below the max overclock temp of 71C ? The card's OC will be limited by the max OC voltage / power draw allowed by the overclocking tool or by the VRM temperature which often increases when a hybrid is used. So again, adding the hybrid GPU cooling accomplishes what ? Being able ti read 55C GPU temps might give you some sense of well being but does nothing to improve the performance of the GPU as oppos\sed to 70C

Here, the board manufacturer has decided to place heat sings at various locations but not at the dead air spot you've photographed. I can only therefore assume that they don't think it's necessary. It is undisputable that heat sinks will improve cooling of these chips, but to what end ?

a) The above recommended "spot cool" fan on the adjustable arm can direct cooling air over whatever you want.
b) The effectiveness of the cooling will be proportional to the delta T (air minus chip temp) and the surface area of the chip
c) Adding a heat sink, will improve the cooling roughly by the ratio of the surface area of the HS to the surface area on the chip. On a small HS, the ratio is generally not large
d) What temp are those chips now....if they are 60C, I see no advantage to be gained by bringing them to 50C

I have got no issue for undertaking this project, if you were doing it just for aesthetics or curiosity, I'm on board and, being a bit of a geek, I'd love to hear the results. But without a known problem "existing", as you don't know just how hot they are getting, I wouldn't expect to see any improvement in OC performance when you are done.

I usually bought such things here... site has been down for a while but "appears" that FCPU is functioning again.

http://www.frozencpu.com/cat/l1/g40/Air_Cooling.html

1. Measure the temp, if still concerned ...
2. Add the spotcool fan, HS is useless without air blowing over it
3. Measure the temp, if still concerned ...
4. Add the HSs

 

[Herr_Koos]

see ?? opinions are like butt holes , everyone got one [lol]

the darn sink kits are like only 20 bucks ? its not like you lost your lifes savings if it don't work out as you expected ?? just a shrug your shoulders thing and move on ??

I'm not located in the States, by the way. Our local currency is around 16 to the dollar and international shipping is unaffordable. Will need to find a place that sells these parts locally, and there is no guarantee I'll even find one.

 

[JackNaylorPE]

I have had stuff shipped by Amazon from China to the states for cheaper than I can buy it here.

FCPU ships internationally, and it was a significant part of their business. Not knowing where you are, can't offer any suggestions buyt the nearest water cooling shop should be able to address your concerns.

 

[Herr_Koos]

Thanks everyone. Consider the matter closed.

 

[InvalidError]

I have had stuff shipped by Amazon from China to the states for cheaper than I can buy it here.

I discovered that only a few months ago, absolutely ridiculous. You can buy parts and gadgets that would retail for $10-30 here (+$5 to $20 in shipping) direct from China for $1-5 including shipping.

 

[junkeymonkey]

if you look over some overcclocker sites you may find posts and how to on making them your self or like this guy just got one large or salvaged from another board cut then to fit ? maybe someone around town got some old /junk motherboards you can get the sinks off them and use on yours ??

http://www.overclock.net/t/1213521/diy-vrm-heat-sinks

 

[junkeymonkey]

'so vendors are now selling hybrid nVidia cards. To what purpose ? The fans on these cards don't even turn on till 65C and running full tilt overclocked to the max, they are running in low 70s. The 980 / 980 Ti don't throttle until they hit 85C''

no sir they throttle at as low as 65c read up some

why do I want a card at 65c idle in my case to start with ?? keeping things cool is hard enough ?? is it not all about cooling and keeping it there ??

and why guys with them ''air'' card go and want a water block at extra added cost ? guys in the know just get a plug and play hybrid and be done with it ??

plenty like this
http://www.overclock.net/t/1528783/msi-gtx-970-gaming-voltage-throttling-at-65-deg

http://www.overclock.net/t/1561166/gtx-980-ti-throttles-at-65-degrees

https://forum-en.msi.com/index.php?topic=253080.0


heck my car don't get but 65c max load with the fan at 35% ?? hybrid cards may on there worst day mite get to 60c and that's a 980 ti ?

so why do I want 60c at idle cooking in my case ??

 

[Lefteris Fousteris]

heatpads and heatsinks are the way to go, they should get some incidental airflow from the cpu heatsing if they are in front of them.

 

[InvalidError]

so why do I want 60c at idle cooking in my case ??

Because 60C is harmless to semiconductors and all other PCB components, so there is no need to waste power and fan/pump wear/noise on cooling it any further. Going lower only makes some people feel a little better.

Another benefit of letting the GPU idle at 60C is that it reduces thermal (mechanical) stresses on the board when the GPU cycles between full-load and low-load/idle. Too much cooling is not necessarily a good thing.

 

[junkeymonkey]

so I guess we take all on pc cooling as myth ? so my card is 60c and I turn it off and on and theres no stress form 0-60c and back but more from my card at 30c idle to 0 ?

- makes sense to me i'll get right on removing the cooling from my rig right away

see like from here

http://forums.evga.com/I-get-my-new-980-TI-FTW-Edition-and-m2447696.aspx

could of got a hybrid and been done with it ..

thing is as I first said it all about your personal choice and experience on what you feel is right for you and your thinking and needs .. like the old saying goes whats good for the goose may not be for the gander and if you don't do it yourself and learn form that experience you really don't know and won't know better next time on what ''YOU'' think is best for ''YOU''

his opinion , my opnion ,the guys down the roads opinion may not be close to any of your own from your own knowledge from experience ..

its a low cost mod easy to do try and see draw your own conclusion in the end -- that's all there is to it