How big of an issue is the VRM overheating problem?

Cooling Processors quietly

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HeyEverybody
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How big of an issue is the VRM overheating problem?

Post by HeyEverybody » Sun Aug 20, 2006 7:16 pm

I have a question about that warning on spcr about tower heatsinks and the vrm components around the processor. How big of a problem is that usually? Wouldn't the best option for keeping the vrm's cool be a cpu cooler that blows straight up and not down or to the side? Does anyone have any recommendations for these types?

Bluefront
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Post by Bluefront » Mon Aug 21, 2006 1:59 am

Apparently it's not a problem for most people......maybe if you over-clock, or run a super-hot system there would be concern.

Airflow? If you blow the CPU fan upward, you are depending on the intake to the actual heatsink to cool the board components. If you blow downward you get a positive airflow over those components.....only slightly warmer. Take your pick. Both configurations work. I worry more about CPU and HD temps than other board temps....

EndoSteel
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Post by EndoSteel » Mon Aug 21, 2006 7:25 am

HeyEverybody
Wouldn't the best option for keeping the vrm's cool be a cpu cooler that blows straight up and not down or to the side?
The best option is to glue heatsinks to them and by a cooler that performs best, irrespective of the design.

cmthomson
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Post by cmthomson » Mon Aug 21, 2006 11:27 am

It depends on what CPU you use.

If you have a relatively cool AMD, or a new Conroe, VRM heating should not be an issue, and yes, you can use a cooler like the XP-120 to move air across the VRM.

If you have a Pentium D, VRM heating is definitely an issue. I eventually killed a motherboard with an 830 D, even with heat sinks glued on and fancy ducts. This is a double whammy: you need a Ninja or similar monster tower to cool the CPU, and that means no VRM airflow without extraordinary effort.

HeyEverybody
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Thanks for the advice

Post by HeyEverybody » Mon Aug 21, 2006 8:58 pm

How would you glue a heatsink to the vrms? What would you use as the glue? I know a lot about pc's but I am kinda new when it comes to custom cooling and overclocking so any help is appreciated.

Gorsnak
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Post by Gorsnak » Mon Aug 21, 2006 9:20 pm

You can get thermal epoxies from Arctic Silver and probably other manufacturers of similar products. Sticky heatpads like those one video ramsinks are probably available too.

cmthomson
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Post by cmthomson » Tue Aug 22, 2006 7:36 am

I've used Swiftech RAMsinks. They come with sticky TIM attached.

HueyCobra
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Post by HueyCobra » Sat Aug 26, 2006 1:45 am

VRM cooling is discussed in Quiet DIY OC'ed Pentium D 830 System, Part Two. Examples of heatsink products with thermal tape include BFG Memory Sinks, OCZ Copper BGA Ramsinks (discontinued), Swiftech MC14 BGA Ramsinks and Zalman ZM-RHS1 RAM heatsinks.

bsdie
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Post by bsdie » Sat Aug 26, 2006 3:05 am

Where should we place the heatsinks?

Im going to pick my computer apart in the coming days and Ive considered putting some spare heatsinks on the hotter components off my passive motherboard. But Im not sure wich components to cooled on the Asus A8N32. The mosfets next to the cpu already have a heatsink, but Ill have 8 spare low profile zalman heatsinks coming with the vf900 that I ordered (my current gpu cooler is a VF700) and I might as well use them.

Image
Think theres any point in adding heatsinks to the red-marked areas? (not even sure if theres clearance, Ill try the 4600+ stock heatsink as my first cooler to se how it does. Theres something geekily perverse about it, but it would feel great to actually use a stock cooler after all these years). And the minor chipsets marked with green circles? Would the heatsinks make a difference?

A8N32-SLI Review

Lawrence Lee
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Post by Lawrence Lee » Sat Aug 26, 2006 9:18 am

I recently switched from a XP-120 to a SI-120 (which is about an inch higher). My PWM temp went up 10C on load to around 60C. It doesn't seem to be causing any stability problems, but it is definitely worrying me. I'm considering switching back even though I'm getting 2-3C CPU temperature improvement. This is an Opteron 165 @ 2.6Ghz on a DFI Ultra-D.

bsdie
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Post by bsdie » Sat Aug 26, 2006 10:54 am

My motherboard is idling at 45c now. It will be interesting to se how the swap from a 7000-cu to the stock amd heatsink will affect temps.

EndoSteel
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Post by EndoSteel » Sun Aug 27, 2006 12:12 am

bsdie
Your mobo already has sinks where they are needed.

Amourek
Transistors are designed to withstand temps up to 110C, so you have nothing to worry about.

bsdie
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Post by bsdie » Sun Aug 27, 2006 1:48 am

Thanks Endosteel =)

cmthomson
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Post by cmthomson » Mon Aug 28, 2006 10:58 am

EndoSteel wrote:bsdie
Your mobo already has sinks where they are needed.

Amourek
Transistors are designed to withstand temps up to 110C, so you have nothing to worry about.
Yep, all the MOSFETs are under those two rectangular heat sinks. The RIO parts you highlighted are inductors. They run hot, but they're just copper wire wrapped around a ferrite core.

MOSFETs are designed for even higher temperatures: typically 165*C. That's at the junction; by the time you get to the sensor on the board, there's probably a 30*C drop. Anyway, if you can touch it without going YOW!! it's cool enough.

sanse
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Post by sanse » Wed Aug 30, 2006 12:13 pm

Amourek wrote:I recently switched from a XP-120 to a SI-120 (which is about an inch higher). My PWM temp went up 10C on load to around 60C. It doesn't seem to be causing any stability problems, but it is definitely worrying me. I'm considering switching back even though I'm getting 2-3C CPU temperature improvement. This is an Opteron 165 @ 2.6Ghz on a DFI Ultra-D.
60C is just a comfortable temp for those semiconductors. dont' worry. they are designed for temps way over 100C.

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