Water-cooling question re: Voltage Regulator Circuit

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Water-cooling question re: Voltage Regulator Circuit

Postposted on Tue Jul 08, 2014 3:52 pm

I don't see this discussed very much - sorry if I missed it but I've been researching CLC / AIO coolers, expandable systems, etc. the past few days and only tomshardware cautioned against disregarding the VR circuit once you replace an air cooler with a water block.

from Tomshardware :

"When replacing the stock CPU air cooler with a water block you are removing the provided cooling to the motherboards voltage regulators, that air flow needs to be substituted with either a direct downdraft cooling fan, or increasing airflow over the entire area."

I have the MSI Big Bang XPower X58 (VR circuit pictured in the link below). That bigass heat sink connected to the 8mm pipe running across the capacitors - does that really need air blowing on it all the time? The past 3 years my HSF has been oriented so the fan pushes air toward the back of the case - the point being I doubt my CPU fan is doing much, if anything to cool that heatsink/pipe.

Have you guys added fans to cool your VR circuit after going to a water-cooling rig?

http://www.hardwaresecrets.com/fullimage.php?image=25783

Thanks for any thoughts you can share!
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Tue Jul 08, 2014 4:33 pm

I would say the heatsinks they put on anything but bargain basement boards are overkill and mostly for looks, like ram heat spreaders, but I feel more comfortable having them there. I just went to newegg and searched for the cheapest asus intel atx board, and it doesn't even have a heatsink on the VRMs.

If you have enough airflow to cool your other components, I would say you are in the clear. Back in the DDR2 days, and when my radiator was outside my P192 case, I burned up a few DDR2 chips, until I put a 120mm fan on top of them ( http://splak.net/computer/watercooled/new/IMG_0352.jpg ). I have a ridiculous amount of airflow through my case now, so its not an issue ( http://i.imgur.com/56Bpdjs.jpg ).
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Tue Jul 08, 2014 4:41 pm

Depending on the placement of the VRMs, not really sure how much air from many tower-style HSFs (the majority of aftermarket CPU air coolers) really contacts the VRM/heat sinks as many configurations have them aimed toward the rear of the case. If I were you, I'd forget about that nonsense. As long as you have some air movement through your case (ie, from intake and exhaust case fans), and aren't trying to push crazy Vcores for overclocking, you should be fine.

Forgetting about VRM cooling for graphics cards when replacing stock coolers with water cooling that does not also cool the VRMs, however, is probably not a good idea.
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Tue Jul 08, 2014 5:28 pm

imo it all depends on if you are overclocking or not

with my system which is heavily overclocked (5ghz 3930k) i have to have some fairly hefty airflow (multiple dedicated fans) over the massive heatsink on my voltage regs or they get over 100 degrees C which i really dont want to happen (i have temp sensors all over the place on my asus x79 sabertooth)

when i run stock they rarely get over nominal room air temperature and probably dont need much cooling at all - if any

so if you are running stock speeds i dont think you would have to worry about it but if you overclock i would seriously think about some kind of air cooling over them
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Wed Jul 09, 2014 6:03 am

thanks you guys I appreciate it - i'll prob throw an 80mm fan in there somewhere, direct it toward the back of the case - seems like the thing to do.
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Wed Jul 09, 2014 10:28 am

Unless it is a cheap motherboard with too few VRM phases and no VRM heatsinks, there's probably not a lot of risk. Power MOSFETs are rated for pretty high temperatures; and while a waterblock or tower-style heatsink may result in less airflow across the VRMs, what airflow there is will probably consist of cooler air than with a traditional downward-blowing HSF.
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Wed Jul 09, 2014 11:21 am

The VRM heatsinks on your board are definitely on the large side. I personally wouldn't worry about it too much considering the AIO fan will (probably) be either above the IO cluster or above the mobo. There's still going to be a fair amount of air moving across the VRM area. Keep in mind, the faster the CPU runs, the more the VRM is working, but the CPU fan is running faster also = more airflow when VRM is hot.

f0d makes a good point. If you have the ability to monitor VRM temps, definitely keep an eye on them. I don't have an exact target temp for you, but like JBI said, MOSFETs are rated to run at relatively high temps. Probably something that is easily Google-able.

My general rule of thumb: When buying a mobo that is destined for even the slightest (ie stock voltage) overclock, get one with VRM heatsinks of some kind. Especially since rigs of that nature are likely to have a tower HSF or AIO. I even go as far as to favor mobos with VRM heatsinks over those without for ALL my purchases (all else being the same between my choices).
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Thu Jul 10, 2014 6:14 am

Thanks JBI, thanks Pete - yes the heatsink along with the pipe that runs across VR circuit is pretty beefy - and then MSI markets the board as using "military-grade" components on the VR circuit, which may not mean much but I did compare a lot of X58 boards and the MSI capacitors, chokes etc. appear to be good quality - along with (what appears to be) a sophisticated "active phase switching" system.

I'll have to research a way to monitor the VR circuit temps - right now I only use RealTemp. Maybe SpeedFan?
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Thu Jul 10, 2014 1:36 pm

canoli wrote:I'll have to research a way to monitor the VR circuit temps

Does it show up in HW Monitor/ (That's what I use)
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Re: Water-cooling question re: Voltage Regulator Circuit

Postposted on Sat Jul 12, 2014 2:42 pm

Thanks Pete - I don't know if it shows up or not - and thanks for the reminder about HW Monitor - had it on my system for 2 years, quit using it in favor of RealTemp360.

Anyway using HWMonitor, under Temperature I have CPU, TMPIN1 and System. I guess the VR circuit isn't one of them...?

Here's a screenshot of what HWMonitor gives me:

https://imageshack.com/i/n6l75svj

Not much info googling around - nobody seems to know since every board/system is different.

Found some info on MSI's forum - seems like TMPIN1 is the IOH. Folks are expressing similar concerns over high temps with water-cooling; they're saying pull apart the heatsink/pipe and replace the TIM. I don't know if it's that critical though - I cranked up the cores, that sensor went to 75C. Unless I see 90C+ I doubt I'll worry about it.

I found Intel's Thermal and Mechanical Design Guide for X58 - interesting reading but not so helpful - unless I can reference the Tcontrol value for the IOH, which isn't exactly the same thing as the VR circuit but maybe close enough?
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