Rolling my own VRM cooling

[APWNH]

I have a mini-ITX build where the motherboard's VRM chips are not adequately cooled. The mobo did not come with any heatsinking on these chips, and it's been determined (see this thread) that thermal-throttling of the OC'd Sandy Bridge CPU can be prevented if the VRM chips are properly cooled.

Problem is there is only about a ~7.5mm wide space on the board that's available for a heatsink to be placed there. There are not any readily available heatsink designs that fit well in this space that provide adequate cooling.

The row of VRM MOSFETs is next to a row of capacitors on one side and a row of chokes on the other side: A rectangular heatsink spanning the width of the VRMs and chokes (18mm wide rather than 7.5mm wide) can fit there if a 11x55x3mm section of it is milled out. (the strip of MOSFETs is 55mm long)

Here's a picture pointing out the components.



I don't have a mill... I can pretty much only try to make something out of some old heatsink using a hacksaw. I did get two 40mm Scythe Mini Kaze fans that I can try to stick in there but with the puny 6mmx6mmx25mm aluminum heatsinks I put there it's not getting the job done.

I've butchered the Southbridge HSF so I can't really RMA it to replace it with this awesome mobo. (A reviewer has his 2500K in that thing at 5.2Ghz? )

So my question is... Does anybody have a small HSF that contains large quantities of copper that they could donate to me? The only hsf I have here that might be suitable for my task (and it'd require a LOT of hacksawing, plus the HSF itself is still probably worth like $40) is a Scythe Ninja+.

Better yet if someone here has access to machining tools...

[DPete27]

Have you looked into any enzotech products? Newegg has the individual heat spreaders for $15 shipped which is what looks to fit your needs (since there are no holes in the board for push pins...and DONT try to drill any)

[APWNH]

You're right, those are probably the best available ready-to-go solutions but I think they'll be just not quite good enough. they might be good enough with the fan I've got there...

But I want something that'll do a better job there.

[just brew it!]

Those Enzotechs look pretty nice, I'd give 'em a go. Along with a little airflow, I think you'll have about the best off-the-shelf solution for what you're attempting here.

(I'm also of the opinion that OCing a mini-ITX is a bit silly, but whatever...)

[APWNH]

I'm of the opinion that OCing a mini-ITX is a bit silly

I'm of the opinion that it's completely awesome. It's all about the performance-to-volume ratio. Hey I've got the regular thermal settings so it idles at 1.6Ghz @.98v.

[just brew it!]

Don't underestimate the benefit of even a small improvement in airflow. If the air ain't moving, temperature of the stagnant air next to the components can be many degrees above ambient, and this makes a huge difference.

Yeah, I suppose maximizing performance-to-volume could be an interesting exercise, but unless you're trying to make something that's actually portable I'm not sure I see the big attraction.

[APWNH]

Well. I haven't actually taken the machine to any LANs yet. The machine's spent most of its life in various states of disassembly. I'm getting close to finishing it. This is one of those finishing touches.

There is airflow back there. It's what the 40mm fan is for.

[just brew it!]

There is airflow back there. It's what the 40mm fan is for.

Ahh, OK. When you said:

I did get two 40mm Scythe Mini Kaze fans that I can try to stick in there

I assumed that meant you weren't using the 40mm fan(s) yet.

[APWNH]

They're not *mounted*. But they aren't moving anywhere on account of how little space there is for it to move to.

What I'd like to do is fabricate some kind of a heatsink that is large enough for me to rig up something to attach the fan to it. Then thermal-epoxy the sucker on the row of chips.

[just brew it!]

Given the cramped quarters, IMO you ought to ditch the idea of attaching the fan directly to the heatsink.

[APWNH]

http://imgur.com/7wVvs

Damn was it difficult to obtain that shot.

You can barely see the fan lying there at an angle. behind the overexposed grey and white cable.

It looks like the HSF pipes will get in the way of a vertical shaft coming out of the area, so yeah i won't be able to have something to mount the fan onto.

[just brew it!]

Took a minute of staring at that pic to tell where the fan even was!

Eeek, that's an airflow/cooling nightmare. With all the cables in the way, you're probably going to have some dead zones unless you somehow manage to stuff a high CFM (read: loud) fan in there somewhere to really get the air moving.

[credible]

Those Enzotechs look pretty nice, I'd give 'em a go. Along with a little airflow, I think you'll have about the best off-the-shelf solution for what you're attempting here.

(I'm also of the opinion that OCing a mini-ITX is a bit silly, but whatever...)

Those are my sentiments as well, just ordered some:)

So far as your situation goes, forgive me if I'm viewing your picture wrong but is that yellow thingy your fan and what of those holes that appear above that, at the top so to speak.

Could you not get a slim sleeved fan and put some double sided sticky tape along the sleeves and have it pulling hot air out through that top part, assuming thats the top, rather then drilling holes I mean, myself, I would drill the holes and put some rubber between the fan and the metal.

[Bocava]

I have never seen a motherboard with ram on it.lol but I guess you can buy any generic heatsinks to cover it up.

[credible]

I have never seen a motherboard with ram on it.lol but I guess you can buy any generic heatsinks to cover it up.

I don't think either of these have memory built in to it, could be wrong though, but I have seen older motherboards with ram built right on to the board.

[just brew it!]

I have never seen a motherboard with ram on it.lol but I guess you can buy any generic heatsinks to cover it up.

I don't think either of these have memory built in to it, could be wrong though, but I have seen older motherboards with ram built right on to the board.

How'd we get onto the subject of RAM on motherboards anyway? Nobody said anything about there being RAM on this board.

Some really old motherboards (Socket 7 timeframe) had a small amount of fast RAM on them that was used as CPU L2 cache, since CPUs back then had very little on-chip cache. Some more recent motherboards have dedicated RAM for the IGP; AMD calls this "SidePort RAM" (not sure if there's an Intel equivalent).

[APWNH]

VRM == voltage regulator module =/= RAM

[DPete27]

Hmm, the solution looks pretty simple to me. You need a new CPU heatsink with a fan. Something that blows down onto the cpu. That will get rid of those noisy 40mm fans, cool the CPU, and provide airflow to the MOSFET heatsinks all with one fan. I have no idea what your size restrictions are, but if you provide some dimensional limits I'm sure we can find you something.

[APWNH]

No, an air cooler will not work well enough for me to OC and at that point I won't need extra cooling for the VRMs. I'll take better pictures when I get home.

[DPete27]

I figured, I thought I saw water cooling hoses in that picture, I didn't read your system specs in your signature close enough. I just don't think you're going to do any better than those enzotech heatsinks, they're cheap enough to give 'em a shot IMO. And something is better than nothing. I'll keep looking...maybe I'll find something that you can mount the fan to for the back row of VRMs. What's the distance from end to end of those 7(?) chips and whats the clearance between the caps and the chokes? Maybe even the whole "L" (9 chips). We might be able to find a wider rectangular heatsink that you can cut into a homemade "L" shape.

[Walkintarget]

I have an HTPC that suffers from poor cooling on the mosfets behind the HSF. Its a tight fit in there, so I purchased a Scythe Shuriken Rev. B. The fan blows upwards, so I thought about flipping the fan to blow down over the heatsink and try and cool the mosfets with that airflow. Has anyone ever tried this with this cooler ?? Its quite popular on an HTPC or SFF build due to its very low height.

[DPete27]

Okay, APWNH. these badboys are the cream of the crop as far as pre-fabricated MOSFET heatsinks are concerned. Maybe one of those will fit in your rig?

@Walkintarget - flipping the fan to blow down onto the motherboard will likely cause your CPU temps to rise ever so slightly, but you should see a greater reduction in temps on your MOSFETs. And if you don't like the results, its easy enough to just flip the fan back over. I would've installed the fan blowing down in the first place, so I'd be curious to see how your temps vary after flipping the fan. Please post your findings. Just don't snipe APWNH's thread.

[UltimateImperative]

Maybe..

Put a higher static pressure fan on the rad, maybe on both sides. Something like a Gentle Typhoon, the new Swiftech fan or the new high-pressure Corsair.

"Mod" your PSU by removing the cables you're not using and possibly shortening the ones that are too long. Only do this if you know what you're doing, since the capacitors in the power supply could potentially shock you.

With those and some heatsinks like the ones DPete27 linked too, it could work.

[APWNH]

Wow DPete27 that's some good work there! Thanks.

Unfortunately the width of the strip of space is under 8mm wide, so even the smallest one at 12mm wide will not fit. The Enzotech copper bits will fit, but I feel like they're simply not tall enough to offer sufficient performance. Perhaps I can thermal-epoxy two "stories" of them to extend them.

I was searching for Gentle Typhoon fans for the main radiator but they were far too difficult to find. I settled for Scythe Kama Flow 2's.

[just brew it!]

The Enzotech copper bits will fit, but I feel like they're simply not tall enough to offer sufficient performance. Perhaps I can thermal-epoxy two "stories" of them to extend them.

Probably a "diminishing returns" sort of thing. The contact area where they'll be epoxied will be quite small, so heat transfer across that interface will be poor. Mechanical strength will be poor as well, and I'd be worried about the top set of heatsinks coming loose and shorting stuff out.

[APWNH]

Right, they'd be connected only by the 4 thin poles, and that connection is not going to be a solid copper connection.

[td1353l]

i have bought the extra vrm sinks from new egg before, just be sure to go to a hardware store and get actual thermal tape. the tape that comes with it is ok, but will always have one or two fall off in a day to two. skip all taht and buy thermal tape now, and stick it on and not worry about it falling off.

[DPete27]

Right, they'd be connected only by the 4 thin poles, and that connection is not going to be a solid copper connection.

Solder them together like copper pipe.

[APWNH]

Right, they'd be connected only by the 4 thin poles, and that connection is not going to be a solid copper connection.

Solder them together like copper pipe.

Brilliant. I'm gonna go order a set (or two) of those sinks now.

Will regular electronics solder work for this? I have two 60W soldering irons and a few propane torches -- I'm pretty sure I've got enough heat to get the job done.

Hmm. Or I could get one of the 13 or 14mm wide Enzotech sinks and hacksaw it down the length of it so I end up with two pieces that are two poles wide. That would be more cost effective and better performing than 3 or so sets of the MOS-C1 mini-sinks. If those little poles are the same size.

Edit: I ordered an Enzotech MST-88 copper heatsink. Will probably cut it up into rectangular pieces. It should work. I should have enough material there to solder together a double-layer monstrosity to place on that row of MOSFETs, with a few shorter pieces left over to stick on a few of the remaining chips.

[just brew it!]

Yeah, regular electronics solder should work for soldering copper heatsinks, provided the heatsinks don't have any sort of coating on them. Just use some sandpaper or a metal file to remove any oxidation prior to attempting to solder them.