Visiontek GeForce2 Ultra Cooling Mods

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How-To build better cooling for this video card. — Nick Pitchford

I decided that the stock HSF/RAMsinks weren’t cutting it at 270 core/505
mem. Hell, you can see though the space between the RAMsinks and RAM
chips! So, time for a mod.

A friend of mine had just gotten back from work with a box full of crap (He takes their surplus ancient materials when they’re being thrown out). I
figured I’d ask him for a large heatsink. It just so happens, he had a
MASSIVE 10″ x 8″ x 1″ heatsink that could only have been used on one of
those ancient 8″ hard drives, I can’t think of anything else that big. He
was creating a spud gun (I wont bore you with details), and had some scraps
left over.

I took a liking to one piece, which was about 4″ x 3″ x 1″. I
had a Delta 60MM fan left over from my old computer, so I trimmed it down
as close to 60mm/60mm as I could, keeping the edges clean by aligning cuts
to pins. Then I put the HSF over the GPU on my card, and drew circles
through the holes in the card.

Holes were then drilled, and countersunk to
keep it burr-free. It had to be lapped of course, no sense modding if it’s
a poor surface. The HSF was black anodized on all sides (Including the
bottom), so I used a file to scrape the anodization off. I then used 220
grit sandpaper to remove the file’s marks. Then came 600 grit paper to
remove the 220 grit paper’s marks. Then a good rubbing with a new sheet of
600 grit, this time wet.

Then a final buffing with a sheet of ordinary
college rule binder paper (Paper is very smooth, and won’t create any
newer, smaller marks). I lapped with each paper using my table. I’m lucky
to have an expensive executive solid oak table, which is perfectly flat (I
checked with a level to ensure a perfect surface), but most people use a
slab of glass.

I got it looking pretty nice, although it could have been much better
(black anodized next to bare aluminum isn’t very attractive).

So how to attach the HSF…It had to be sturdy, and I didn’t have any
thermal adhesive, nor did I want to spend $18 on any. The only other way
would be via mechanical means–bolts. On my GeForce256, I used bolts to
secure a larger HSF on. What had happened was the card bent just enough
under the pressure of the bolts so that a gap appeared between the HSF and
GPU.

There wasn’t any way around that problem, keeping it loose enough not
to bend the card would yield poor contact between the 2
surfaces. Tightening it too much would result in a cracked
card. Tightening it just a little resulted in a bent card, which would not
allow optimum heat transfer.

So how could I solve this problem?

Pretty simple–make it so that the force of the bolts is concentrated directly
behind the GPU, as opposed to on either side of it, as dictated by hole
placement on the card.

I had a 3′ x 3″ x 1/8″ aluminum strip left over from another project, so I
devised a way to use that. I cut, bent, and filed it into this shape:

Clip

That shape would allow airflow under the retaining plate, which would aid
in cooling the back of the card (never mind the flat plate for now, I’ll
explain later).

I needed to purchase bolts long enough to be used, however, so I went to
the Overclocker’s Hardware Supply Store, also known as the Home Depot. I
picked up a package of 1½” x 1/16″ bolts and a package of appropriate
nuts.

Continuing with the proper supplies, I fashioned a retaining plate
out of the aluminum strip. I rounded all the edges off, then placed the
retaining plate on the back of the card where I wanted it to reside, then
drew circles on it through the holes on the card.

At this point that I noticed a problem: The retaining plate would put all
its pressure on the card’s components (transistors, resistors, capacitors,
etc), not the PCB itself. I didn’t want to damage any of the components on the back of the card, so I had to brainstorm for all of 2 minutes. I ended up making a small riser to put between the retainer plate and the PCB. You can see it in place here:

Riser

Ho-boy, another problem: The components on the back of the card would not
allow this riser to fit. I had to file the corners off to fit between
the components. I don’t have actual photos of it, that would require the
disassembly of my card again which is a serious pain, but I do have a
drawing I whipped up. This is the approximate size and shape of it:

Riser 2

The aluminum was 1/8″ thick, so I had to take my now non-square riser and
file it down to about 1.5mm thick. Creative, effective, and most
importantly – safe. With it filed down, pressure is spread over the
PCB area between components, as well as a small amount on the uniform
surfaces of the components.

I placed the HSF on the card, placed the bolts in the holes, placed the
retainer clip on the back, struggled with the bolts trying to get the nuts
on them for about 15 minutes, then tested the placement out without turning
on my rig. Cherry, everything worked fine.

I took it apart again, applied
Arctic Silver II between the HSF and GPU and used small squares of Frag
tape between the retaining plate and riser and between the riser and card
PCB/card components. I used Frag tape to prevent any contacts from being
shorted, which ASII would have done an admirable job of.

I attached the fan with simple 1″ wood screws, and used some thick steel
wire to bind the pins together, holding the screw’s threads in place.

As for the RAM sinks, it’s a lot simpler.

I popped (literally) the old
ones off the card using a toothpick (I know, they should have been harder
to take off, but these just came right off). I had a Foxconn Celeron
passive heatsink lying in my Assorted Parts-N-Crap drawer, so I decided to
use that. It had large, sparse, thick fins, ideal for smooth airflow.

I
cut it lengthwise, then trimmed off the ends to the appropriate size. I
tested it out on the card and found that the fan would interfere with the
top of RAMsink’s fins when installed in the correct place. You can see
here that I cut little bits out of each fin using a hacksaw in order to fit around the fan:

Wide

And here (It’s more clear on the left RAMsink):

Wide 2

I attached the RAMsinks using a dollop of epoxy (Just your standard 5
minute set epoxy, it’s all I had lying around) on the corner of each RAM
chip, and covered the rest of the surface of the chips with an unusually
thick layer of ASII.

It had to be thick because epoxy can’t be smushed
down as thin as ASII is supposed to be. Still though, a 0.2mm thick layer
of ASII is a lot more effective than that crappy glue they used on the stock
RAMsinks. Again, no actual pics because that would require disassembly,
but here’s a drawing of where each material is:

Epoxy

In case you’re wondering what the tape is for, it’s to divert flow towards
the RAMsinks. There is a little space so that some air can get through,
but most of it is sent towards the RAMsinks.

This all took place about a month and a half ago, when I was using a BCM
QS754 motherboard for my Athlon Slot-A. I recently acquired an Abit K7A,
which brought with it another problem: The Abit has an ISA slot, so the
PCI and AGP slots were about a half inch higher on the K7A then on the
QS754. This wouldn’t be a problem, but the retaining plate was just too
tall to fit. I had to re-manufacture a new plate, this time a flat one.

The flat one, pictured above, doesn’t look as nifty as the bent one, nor is
it as effective. It can be bent if the bolts are tightened hard enough,
whereas the shaped plate was completely solid. I set the shaped one on my
garage floor, which I had used to hammer it plum and square, then I stood
on it. It did not bend at all. You might not think that’s a big deal, but I weigh 360lbs+, not a modest weight at all.

After I had cut another portion from my aluminum strip and drilled holes,
ANOTHER problem came up. The holes would not allow the bolts to pass
through – they were off by 1mm. I had to spin the plate around and drill
holes on the opposite side (Also pictured above).

In addition to creating a new retaining plate, I had to cut about 7mm off
one of the bolts. All that was required was a hacksaw and a pair of
vice-grips.

Now keep in mind that I didn’t tighten the bolts until the card splintered
into a thousand pointy shards. I tightened each nut as hard as I could by
hand, then turned them each 1/4 turn with a pair of pliers. This assures
that it wont be too tight, but it will most certainly be steady enough
(wriggling the HSF results in the entire card moving with it, it’s solid as a brick of granite).

So that’s it. Done deal. Modding over. What did all that toil and
trouble get me? Why, it got me 50 MHz on the core, and a respectable 77 MHz on the RAM, over stock speeds. That would bring my clock speeds to
290/535, not too shabby. Not the best O/C in the world, but it’s quite an
improvement over stock.

Some more pics for ya:

In Case

In Case 2

And one of my card bathed in gorgeous blue light (That’s another article
for another day =P ):

Neon

Nick Pitchford

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