Replacing the GPU Heatsink on Radeon X700

P

psistormyamato

I have a Radeon X700 PCIe card with a old, noisy fan that desperately
needs to be replaced. I have always hated the high-pitched screen that
this little bugger emits, so I was thinking about replacing the stock
heatsink/fan with a lone heatsink on the GPU and a larger diameter PCI
fan in the adjacent PCI slot. I imagine that this setup will
sufficiently cool the GPU and, at the same time, reduce noise by
allowing the same amount of air to be moved by the larger fan that can
do the same job at lower RPMs.

When I removed the stock heatsink/fan, I noticed that the thermal
interface consisted of what looked like 2 thermal pads that were
joined with some kind of "fluffy" gray substance. I also noticed that
there are about a dozen little transistor looking things sticking out
of the top of the GPU in various places.

So, what would you suggest that I use for a thermal interface?

It seemed that the thermal pads were, perhaps intentionally, keeping
the heatsink/fan serveral millimeters above the "little transistor
looking things", so that they did not make contact with each other.

Is it important that my new heatsink should not come in contact with
these "transistors"? If so, then should I simply leave the pre-
existing thermal pad on the GPU side, remove all the old, gray fluffy
material on it, put a thermal pad on the new heatsink, and use a drop
of some kind of thermal grease to mate the two surfaces with?

If it weren't for those little "transistors" sticking out, preventing
a flat mating of the two surfaces, then I would just use some of that
Arctic Silver that everyone keeps orgasmicly referring to. But I am
uncertain what the best course of action would be, considering that
these "transistors" are in the way.
 
F

First of One

Usually the small resistors on the GPU's green package are below the level
of the die's top surface, so a flat heat sink will not touch the resistors.
It's actually pretty uncommon to see thick thermal pads on the GPU, unless
it's there to fill the gap created by a shim around the GPU package (as is
the case with the original 9700 Pro).

Why don't you take a close-up photo of the GPU, post it on www.imageshack.us
, and link it here?
 
P

psistormyamato

I couldn't get the focus proper on this old digital camera, so it's a
little fuzzy, but you can still see it pretty good. I would have tried
to sharpen it up a bit, but I don't have any imaging applications on
the PC I'm using at the moment. Though, you might try to sharpen it a
little yourself if you want.

The card:
http://img215.imageshack.us/my.php?image=im000215aa6.jpg
http://img252.imageshack.us/my.php?image=im000217zz5.jpg

The heatsink/fan:
http://img512.imageshack.us/my.php?image=im000220kd6.jpg
 
F

First of One

No amount of Photoshop sharpening will get more detail in a blurry spot. :)

Again, usually the small resistors on the GPU's green package are below the
level of the die's top surface. You should confirm this with a straight edge
(e.g. steel ruler). If that is indeed the case, you can use any aftermarket
cooler on the GPU, like the excellent Zalman VF900:
http://www.newegg.com/Product/Product.aspx?Item=N82E16835118001

The stock X700 HSF also cools the RAM, so be sure to put small heat sinks on
the RAM chips. The VF900 package includes 8 RAM sinks.
 
P

psistormyamato

That Zalman fan looks pretty good. But the package only includes
thermal grease. Wouldn't I also need some thermal epoxy to attach the
RAM sinks securely?

I'm still concerned about any physical contact with those
"transistors" that are sticking out. Could that lead to a short? Or
would direct physical contact actually help to transfer heat more
effectively?

Also, I was wondering about the 3-pin connector. I can still connect
the Zalman's 3-pin to the card's 2-pin output, right? Isn't that 3rd
pin just for a speed sensor?

And, since the card is expecting to control a small fan, how effective
is the conversion of RPMs for the large fan? Is that primarily what
that controller, that comes in the Zalman package, is for?
 
F

First of One

That Zalman fan looks pretty good. But the package only includes
thermal grease. Wouldn't I also need some thermal epoxy to attach the
RAM sinks securely?

Each RAM sink has a pre-applied thermal pad on the bottom. Just remove the
adhesive backing and stick the sink on the RAM chip.
I'm still concerned about any physical contact with those
"transistors" that are sticking out. Could that lead to a short? Or
would direct physical contact actually help to transfer heat more
effectively?

Take a look at the 9800Pro I used to own:
http://img136.imageshack.us/my.php?image=nosinkaq2.jpg

The resistors on the chip package are quite common. Their height is usually
~1 mm below the top surface of the die, so a flat heat sink won't contact
them. You can confirm this on your card by first cleaning off the residue
from the die (use isopropyl alcohol), then putting a ruler against the die.

If the ruler check proves inconclusive, just cover the resistors with scotch
tape.
Also, I was wondering about the 3-pin connector. I can still connect
the Zalman's 3-pin to the card's 2-pin output, right? Isn't that 3rd
pin just for a speed sensor?

And, since the card is expecting to control a small fan, how effective
is the conversion of RPMs for the large fan? Is that primarily what
that controller, that comes in the Zalman package, is for?

The Zalman does not plug into the card. It connects to a 4-pin molex from
your power supply. The little black box is a manual fan speed adjuster that
you can optionally use. Many people skip the adjuster and just run the fan
at 100% speed all the time. The fan is quiet enough that you likely won't
hear it over the other fans in the system.
 
P

psistormyamato

Take a look at the 9800Pro I used to own:http://img136.imageshack.us/my.php?image=nosinkaq2.jpg

The resistors on the chip package are quite common. Their height is usually
~1 mm below the top surface of the die, so a flat heat sink won't contact
them. You can confirm this on your card by first cleaning off the residue
from the die (use isopropyl alcohol), then putting a ruler against the die.

Oh OK, I hadn't scraped that gunk off yet, so I just assumed that the
surface underneath was just as low as the rest of the flat area around
it. Thanks for the pic.
The Zalman does not plug into the card. It connects to a 4-pin molex from
your power supply. The little black box is a manual fan speed adjuster that
you can optionally use. Many people skip the adjuster and just run the fan
at 100% speed all the time. The fan is quiet enough that you likely won't
hear it over the other fans in the system.

Oh OK, I saw the image at that website at just assumed that it was a
direct connection to the card.
http://www.newegg.com/Product/ShowI...tion=ZALMAN+VF900+%u2013+CU+2+Ball+VGA+Cooler

But that 3-pin apparently just connects to that cable that has the
visible molex on one end.
http://www.newegg.com/Product/ShowI...tion=ZALMAN+VF900+%u2013+CU+2+Ball+VGA+Cooler

I guess they just used a regular case fan in their design. That would
explain the 3-pin connector.

Thanks for all the help.
 
D

Dummy For Ever

Try using a good quality thermal paste on the GPU, my personal preference is
Artic Silver 5
 
M

Mike Ray

I have a Radeon X700 PCIe card with a old, noisy fan that desperately
needs to be replaced. I have always hated the high-pitched screen that
this little bugger emits, so I was thinking about replacing the stock
heatsink/fan with a lone heatsink on the GPU and a larger diameter PCI
fan in the adjacent PCI slot. I imagine that this setup will
sufficiently cool the GPU and, at the same time, reduce noise by
allowing the same amount of air to be moved by the larger fan that can
do the same job at lower RPMs.


I replaced the stock fan on my X700 a week after I got it. I got a
Arctic Cooling AVC-AT1R2 for about $25. It is silent and works great.
-Mike
 
F

First of One

Problem with this otherwise well-engineered cooler:
1) Discontinued
2) No heatsinks or heatspreader included for the RAM, though they could of
course be purchased separately.
 
P

psistormyamato

I replaced the stock fan on my X700 a week after I got it. I got a
Arctic Cooling AVC-AT1R2 for about $25. It is silent and works great.
-Mike

I would also be concerned about the disruption on airflow across the
mainboard. If air is being forced in at the PCI slots and then sucked
right back out just a few inches later at the system fan, then why
would any air be pulled in from anywhere else?
 
F

First of One

1) You got the fan direction confused. The AC Silencer series of coolers
*exhaust* air through the PCI slot grille.

2) You really should have a decent intake fan installed at the front of your
case to pull in air actively.

This is getting silly. It's not like the X700 puts out much heat. Even the
X800 Pro draws less than 50W. Any aftermarket cooler will work.
 

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