Poorman’s Abit NF7 Series Chipset/Mosfet Cooling

Inexpensive chip cooling – Brian Berryman

HS

I acquired an Abit NF7-S motherboard a while back with the intention of building a gaming system around it. While building this system, I read numerous posts in the Overclockers Forum discussing additional motherboard cooling options and methods for this series of board. When this board is pushed, and pushed hard, some issues crop up due to insufficient, or non-existant, cooling solutions.

This article outlines a couple of cheap (possibly free!) solutions that work. You may have the items I’ve used here sitting in a junk drawer or box and not even considered using them. Some of these items I’ve pulled from “side of the road” finds. In all honesty, I spent more on the pack of butts sitting on the desk in front of me than the parts I’m using in this article.

While the title of this thread states “Abit NF7 Series” (and applies to the NF7, -M, and -S 1.0 thru 2.0 variants), a lot of these ideas will work on other boards, notably other nForce chipset based motherboards. The Northbridge chipset cooling solution outlined here will also work on various graphics cards as well (mostly thinking of GF2 and GF3 cards here), provided the heatsink mounting holes spacing measurements are accommodated for when cutting.

So, let’s get to work, and cool some chips.
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Brian Berryman – aka “Mr B”, Overclockers Forums Moderator.

nForce Cooling From The Land of DOS

Let’s start off with that all important Northbridge.

I’ve got a couple of boxes full of odds and ends from various machines I’ve stripped over the years – mostly i486/early Pentium era stuff from dead OEM machines. Every so often, I’ll find an old PC on the side of the road, waiting for the garbage truck to come and take it away. Occasionally, I’ll get really lucky and find some working drives in them too… LOL.

I was rummaging through one of those junk boxes one day and something came to mind. The old 50mm square i486/Pentium HSF (heatsink and fan) is just about the same size as the waterblock I’m using for the Northbridge on my NF7-S. I got out the OEM Abit NB (Northbridge) cooler which I had put away after removing it, and put the two together, base to base; I found they match up pretty close. With a little reworking, it will fit right on the nForce NB.

The tools I used:

Tools

Got them? Get them! USE THEM! (the dustmask is optional, glasses are NOT).

Disc

Heed this warning!

I can’t stress that enough if you’re using power tools like these. I used to work with a guy who damn near lost his eyesight because he took his glasses off for one minute. I used to think “Oh, I’ll be careful.” and “It won’t happen to me.” Today I use my safety glasses, period.

Tool

The tool itself – air powered, and very fast.

Now I realize not everyone has access to these types of tools (automotive grade air tools), but if you do, boy does it make quick work of this heatsink mod. A hacksaw or similar will work just fine – it’ll just take longer to finish. Either way, you’ll need a small hand file to dress up the edges a bit when your done. If you don’t have one of those, swipe one of your (insert female relative’s name here) fingernail emery boards. =) They work great for this…

I started by marking the base of the sink where the OEM Abit cooler’s mount pins are, to give me reference of how much material (fins) I needed to cut off. Only a couple of them had to be removed. I then chucked the heatsink in a bench vise, to hold it steady, and to allow me to hold the whizzer with both hands. You’ll be making two cuts on the two opposite corners, the first one removes the fins…

Cut 1

…the second cuts the mounting slot in the base:

Cut 2

If you want to get a bit fancier, you could drill a hole like the OEM cooler has instead of slotting the sink. Slotting it gives you a bit more “room for error” if you miss the exact spot to drill slightly. Plus it makes it a little more versatile, in that it can be used on other applications with slightly different mount spacings. If by chance you cut the slot a little bit too wide, simply use a small flat washer on the mount pin to compensate.

All four cuts (two each on opposing corners) took me about two minutes time, including flipping the sink over in the vise, using the whizzer. Again, a hacksaw (or similar) will work fine, just slower. Touch up the rough edges with a file. You’ll probably want to “lap” the sink before you actually install it, as these old sinks don’t usually have the smoothest surface in the world. A touch of spray paint on the bare aluminum adds a finishing touch.

Don’t forget the thermal compound when you put it on… ;)

Sinks

I’ve included above an old chipset sink from a 440BX era Soyo motherboard for size reference. If it’ll fit, which would you rather use??

The fan gets attached to the two unaltered corners like it originally was. One of these days, I’m going to pick up one of these fans HERE, as it puts out a good deal of airflow (16+ CFM) for a 50mm fan.
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Brian Berryman – aka “Mr B”, Overclockers Forums Moderator.

South of the (AGP) border…

As motherboard technologies advance and more and more features become “integrated”, the often overlooked Southbridge chip is handling more duties than ever before and running warmer in the process. Passive or even active cooling for this chip is rapidly becoming a requirement, especially when heavily overclocking.

Besides it’s usual duties, the SB (southbridge) on the NF7-S Series also incorporates the SoundStorm audio functions integrated on this motherboard. Out of the box, there is no cooling solution whatsoever used on the SB chip.

A quick perusal of the AMD Abit motherboard topic in the forums HERE will turn up a good number of threads dealing specifically with this subject. Many users have found when pushing this board to 200 FSB (400DDR) any beyond, sound quality issues from the onboard SoundStorm result. The usual complaint is a “crackling” or “skipping” in the audio, usually when playing games, myself included.

Let’s face it… the majority of owners of this motherboard bought it for two reasons; overclocking and gaming. And when doing the former starts affecting the performance of the latter, solutions need to be found.

Unfortunately, as motherboards become more integrated, there’s usually less and less room around the SB chip itself to attach anything to it. The usual remedy for the NF7-S is to attach a NB heatsink to it. The old style 40mm sink (like the Soyo item pictured earlier) fits easily, but isn’t very beefy. Going much bigger than that however, is difficult, due to the close proximity of the AGP slot, IDE sockets, and a pair of capacitors between the AGP and 1st PCI slot.

If the cooling solution is too wide, it won’t fit between those caps and the IDE sockets; if it’s too tall, and it might not clear the graphics card you’re using. My solution for this also comes from the “Land of DOS”… =)

3 Sinks

This old i486 CPU HSF is something I bought several of on e-BAY a long time ago. I got them originally to use the attached 40mm fans on the graphics cards I was using at the time (GeForce 2 MX200 series). I got 20 of these HSF’s for the same price Radio Shack wanted for a single 40mm fan, new.

Over time, I’ve used the fans on various motherboards as well, putting them on NB sinks like that Soyo example above, and cut up some of the sinks to attach to clock generators and other small chips on those motherboards. The sink measures around 46mm square and is a little more substantial than the Soyo piece.

Attaching it to the Abit SB chip involves a bit more effort, as there aren’t any mounting holes to use. A number of options can be used. Thermal tape, while not the best, is easily removable, if needed. A 50/50 mixture of Arctic Silver thermal compound and Arctic Silver thermal adhesive is much better, but less “removable”. Further still is straight thermal compound, with a very small drop of super glue on two or four corners of the sink to hold it on. I opted for the thermal tape.

Fit

As you can see, this sink just barely fits between the caps and those sockets. Finding one of these exact heatsinks might be difficult, so some improvisation might be required. Cutting a couple rows off of one of the 50mm sinks I used for the Northbridge cooling solution is one option, if the height of it will clear you graphics card.

Either way, if you have one of these boards, it’s highly recommended that you utilize some form of cooling, be it passive or active, on the SB chip. If you use an active cooling solution, Abit provided a fan power header just below the main ATX power socket that’s close enough for the average fan lead to reach.
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Brian Berryman – aka “Mr B”, Overclockers Forums Moderator.

MOSFET Cooling

This is one item that gets a lot of attention in the Abit motherboard topic, between posts about Southbridge cooling. It’s debated whether or not there’s any benefit to cooling these. Some swear by it, others see no reason to. I’ve installed a passive heatsink on mine and while I haven’t seen any miraculous increase in overclockability or system stability, it sure does look pretty. =)

HS

These sinks are designed to be attached to the memory chips on various graphics cards. I got a pair of these second hand, with a ThermalTake Chrome Orb chipset cooler quite some time ago (they weren’t actually part of the ThermalTake kit, I just got them with it…), and as I’ve never had a graphics card with memory in the right places to use them, they’ve been kicking about in the “junk drawer” since then. ThermalTake does, however, make heatsinks very similar to these, which are slightly bigger (and blue).

The CompUSA near me sells these chrome pieces (2 sinks for $10.00), which I think is a bit expensive. I used it because I had them, but I might look into other sinks before I spent a sawbuck for them. You’re already going to need to do some cutting and filing to make this fit on the MOSFETs, so carving up an old sink like or similar to the one I used for the Northbridge at the beginning of this article is a cheap alternative.

This chrome piece is just long and wide enough to cover all six MOSFETs, if it is notched in three spots to clear the capacitors between them. After carefully measuring the spacing, I marked the sink where it needed to be cut and started filing. These chrome sinks I got came with some thermal tape, which I used to attach it when I finished reshaping it.

Mosfet

Chrome finned MOSFET cooling goodness. =)

Are there better cooling solutions available commercially?

Yes. But remember, this is the “Poorman’s” cooling solution. If you don’t have a couple of these old CPU heatsinks handy, you might try asking politely at your local PC repair shop. Bring the guy a coffee first thing on a Saturday morning right when he’s opening up shop, and who knows? =)

Cheers!

Credits and Miscellany

I’d like to thank the Owners, Staff, and Members of the Overclockers Forums, for sharing with me their knowledge of all things computer, advice and wisdom that allows me to be creative and experiment and find new solutions like these. I am indebted to you all. Thanks!

Special thanks to David Greenfield, for manning the digital camera and taking some of the pictures for this article! Thank you!

Extra special thanks to Karen and Jay Hendrix, for letting me borrow the digital camera again…. Thank you!

Last, but certainly not least, thanks, hugs and kisses, to my wife Deborah. Love you…… xoxoxox

The cutting tool used in this article can be found commercially at most automotive tool distributors, and can also be found online at various sites. HERE is but one source. Don’t forget the eye protection!

CompUSA has those memory heatsinks HERE. Searching around might find them elsewhere, and cheaper.

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