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Modding the Zalman 9500 Heatsink

Posted: Tue Nov 22, 2005 6:01 pm
by MikeC

Posted: Tue Nov 22, 2005 6:34 pm
by theyangster
not frontpage? :wink: or not yet?

cool though

120 fan mod looks very cool

Posted: Tue Nov 22, 2005 9:43 pm
by ryboto
i did this mod...with an nmb panaflo...only trouble was the bearing made more noise than the zalman, and I haven't had the time to try a different fan...christmas is around the corner, nothing says stocking stuffer like a couple of panaflos, acoustifans and nexus's!

Posted: Tue Nov 22, 2005 10:47 pm
by Erssa
Looks really nice. Although at these prices and with all the trouble I'd rather buy a reserator. Too bad zalman doesn't include better stock fans or design the heatsinks so the fan swap would be easier.

Posted: Wed Nov 23, 2005 9:41 am
by nici
The 120mm fan used looks like the Zalman fan used in the 7700.

Posted: Wed Nov 23, 2005 11:39 am
by toaom
I had a different idea, but am still waiting for the 9500 to be delivered...
I was thinking of bolting two 12cm nexusses against both sides of the zalman. Or one nexus and a piece of aluminum.

This would give a nice push/pull effect.

Could this be any good?

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2 fans
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1 fan + aluminum plate
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Posted: Wed Nov 23, 2005 8:18 pm
by Mats
nici wrote:The 120mm fan used looks like the Zalman fan used in the 7700.
I think so too, you can see on the latest pic that the holes were there from the beginning, a curve in the in the back of the fan made of plastic shows it.

Posted: Wed Nov 23, 2005 8:24 pm
by theyangster
so it did make it :)

so the 120 fan mystery is solved

what if you put a shroud around the whole thing....

Posted: Wed Nov 23, 2005 9:10 pm
by mg1394
The detailed "how to" is sure to be very helpful to quite a number of folk. Therefore a quote from the article: "The next photo shows the tiny holes drilled into two of the arms that extend from the center of the fan. They had to be very precisely done." could use a bit of engineering revision to specify precisely what size drill bit is used to get the "tiny" hole. Thanks.

Posted: Wed Nov 23, 2005 10:01 pm
by MikeC
mg1394 wrote:The detailed "how to" is sure to be very helpful to quite a number of folk. Therefore a quote from the article: "The next photo shows the tiny holes drilled into two of the arms that extend from the center of the fan. They had to be very precisely done." could use a bit of engineering revision to specify precisely what size drill bit is used to get the "tiny" hole. Thanks.
That occurred to me too, but only long after all the tools were put away. There's no way I will try to guess which size bit it was. I can say I chose a bit slightly smaller than the screw when put up right against it. The plastic is soft enolugh that the machine screw cuts its own thread into the hole.

Posted: Sat Nov 26, 2005 11:12 am
by gleech
can someone explain how the push/pull effect works....

Posted: Sat Nov 26, 2005 11:33 am
by MikeC
gleech wrote:can someone explain how the push/pull effect works....
In this context, it doesn't. The main benefit is that it increases the total pressure through the space between the two fans. But NOT the airflow, which is still limited to the slower of the 2 fans (if they are of different speeds). It's useful when there is higher impedance -- obstructions -- to the flow of air. More pressure means more flow in such a case. With the Zalman 9500, my feeling is that the impedance is very low , so a push-pull set up would not benefit cooling much. But probably fun to play with anyway.

Posted: Tue Nov 29, 2005 9:28 am
by wundi
Mike, any chance of a similar article with the VF700? Maybe after the VGA cooler review (Zalman & AC) has been finished?

Posted: Sun Dec 04, 2005 2:56 pm
by gleech
just got my 9500, any new mod w/ 120mm fan, please share your pictures, i'm planning on modding my 9500 w/ 120mm fan....

Posted: Fri Dec 16, 2005 3:39 pm
by McBanjo
Would it be possibly to cut of the finns on the fanside a bit to fit in a 120mm fan? Or that would be pointless and no cooling gain vs a 92mm fan surrounded by fins?

Posted: Fri Dec 16, 2005 5:05 pm
by Weldingheart
McBanjo wrote:Would it be possibly to cut of the finns on the fanside a bit to fit in a 120mm fan? Or that would be pointless and no cooling gain vs a 92mm fan surrounded by fins?
like this?

Posted: Fri Dec 16, 2005 5:31 pm
by McBanjo
Oops, missed that he did that. Only thought he added a 120mm fan straight on

Posted: Fri Dec 16, 2005 6:12 pm
by gleech
oh, i dont like cutting the fins, it dont looks right, any new mods please share your pics....

Posted: Sun Dec 18, 2005 7:22 am
by KinoSprell
Sorry if this is a "stupid" question, but when it says "°C Rise: Temperature rise above ambient at load", does that mean lower numbers are better?

When comparing the stock and the Nexus fan, it seems the stock one has more airflow @ 5V than the Nexus has @ 12V. When used in a system with a hotter CPU will the Nexus move too little air? Are there other fans with lower noise than the stock one, but with better airflow than the Nexus, or maybe even the stock one?

I'm considering this cooler in my HTPC based on the A-Tech 4000EX, but have not decided on CPU yet (AMD/Intel). The fact that it blows air sideways instead of right down on the mobo is what appeals to me with the 9500, it'll move hot air out of the case with less turbulence. :)

Posted: Sun Dec 18, 2005 8:23 am
by Weldingheart
KinoSprell wrote:"°C Rise: Temperature rise above ambient at load", does that mean lower numbers are better?
Yes
KinoSprell wrote:When comparing the stock and the Nexus fan, it seems the stock one has more airflow @ 5V than the Nexus has @ 12V. When used in a system with a hotter CPU will the Nexus move too little air? Are there other fans with lower noise than the stock one, but with better airflow than the Nexus, or maybe even the stock one?
How could it move too little air?if you aim for silent pc that number is enough,considering you optimized your choice on case and other components,many people here even undervolt the Nexus to lower rpm.

For 'higher' low noise fans,you should look at recomended fans section also fans&control forum subsection,there would be a lot of Nexus alternative which also may come to more affordable price.
KinoSprell wrote: I'm considering this cooler in my HTPC based on the A-Tech 4000EX, but have not decided on CPU yet (AMD/Intel). The fact that it blows air sideways instead of right down on the mobo is what appeals to me with the 9500, it'll move hot air out of the case with less turbulence. :)
Nice case there 8) ,love the A-tech's

Posted: Sun Dec 18, 2005 11:06 am
by Devonavar
KinoSprell wrote:When comparing the stock and the Nexus fan, it seems the stock one has more airflow @ 5V than the Nexus has @ 12V. When used in a system with a hotter CPU will the Nexus move too little air? Are there other fans with lower noise than the stock one, but with better airflow than the Nexus, or maybe even the stock one?
Whether it moves "too little" air will depend on what CPU you're using. Obviously, the amount of heat you expect the heatsink to deal with will affect how slowly you can run the fan.

However, for each CPU/heatsink combination, there is an optimum threshold for airflow. Above this threshold, the benefit of increasing the fan speed diminishes quickly, as the amount of airflow is no longer the limiting factor. Below the threshold, cooling performance degrades quickly when airflow is reduced.

The Zalman 9500 is actually very tolerant to low airflow situations. When faced with an amount of airflow below its tolerance level, it doesn't lose performance as quickly as some other heatsinks. In our particular test, we hit the threshold somewhere between 9V and 12V with the Nexus fan. If you can get hold of a CPU with similar heat to our test CPU (i.e. a mid-range AMD CPU), you should have no problem using the Nexus.

Posted: Sun Dec 18, 2005 12:52 pm
by KinoSprell
Thanks for the replies, I'm learning new things every day here at SPCR :)

I havent decided on CPU yet, but A64 4000+, P4 660 and P-D 830 are within budget. I guess the best way to find out what I need is to run the stock fan @5V (18°C Rise, 22dBA) and see if temp is comfortable, and if so do the mod with Nexus fan starting @12V (21°C Rise, 20dBA).

Posted: Wed Dec 21, 2005 6:08 am
by dwswager
My take on the mod:

120mm fan would work OK as Zalman has provided a decent mounting location. One might even build a different bracket.

Orient the 9500 opposite the rear case fans and turn the fan around such that it is pushing air through the 9500 out toward the case fans.

Keep the frame on the 120mm fan. I suspect there will be signifiant losses out the ends of the blades.

Posted: Wed Dec 21, 2005 6:59 am
by McBanjo
I've been thinking about the airloss at the sides. Not sure since I don't have the cooler yet so it might not bea doable but anyway, the theory:
Cutting the fins almost off, that part that is on the side of the fan, so they have about 0.5-1mm copper left and then twist them around so the outside is inside and inside is outside. It would give you more room for a bigger fan yet keep that cooling-area.

Probibly have to remove the fins to do that (is it possibly?) and not sure the extra space is enought. Otherwise I'll probibly manifacture some sort of frame. The ones that is on the fan is a bit on the heavy side for me.
Without the frame the cooling-effect might not be worth the modding, only worth it for the silence-effect then.

Posted: Thu Dec 22, 2005 2:52 pm
by KinoSprell
Cutting the copper I think is a bad idea. Heat moves like current, if you cut the fins down to 0.5mm at one place the resistance will be much greater, reducing the overall performance of the HS. Soldering the twisted parts might help a little.

Another theory: Looking at the picture with the 120mm mod, it looks like the frame of the fan would just fit outside the HS. How about picking up 5-6 old 120mm fans from the trash and use their frames to make an airtunnel around the HS? Just cut a little part of the bottom of the frames to make room for the heatpipes.

Posted: Fri Dec 23, 2005 4:51 am
by McBanjo
It will be a minor loss ofcourse but might be worth it, it's bether than cuting the copper right off ;-P

A windtunnel will be good if you want to maximise the cfm from the cpu-fan itself but overall I belive you will lose cooling since you'll lose the chassi-fans cooling ability. Might raise sound a bit too, not sure on that tho.

Posted: Sat Dec 24, 2005 4:43 am
by gleech
here is my modded zalman 9500:

First the 120mm Fan:

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My Custom Made Aluminun Bracket:

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Look at the Fan and the Bracket:

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Zalman stock fan and the 120mm fan with the bracket:

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Modded Zalman 9500:

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Posted: Sun Dec 25, 2005 6:18 am
by EricTerminator
Wow, I love it ! :P
I hope it's not too heavy for the socket. :?

See you

Posted: Sun Dec 25, 2005 9:23 am
by McBanjo
Any problem mounting that monster? :-P
Looks neat, got any numbers for it?

Posted: Sun Dec 25, 2005 12:51 pm
by gleech
@MCBanjo

Well as of now I havent tried this monster because I'm saving this for my future upgrade with opteron.

I might re-mod this by changing the 92mm with 120mm fan. and changing the airflow.

do you guys have any suggestion on the airflow, I'll post the diagram of the airflow:

Diagram A: (Current)


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Diagram B:


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Help me decide my final mod, please give your feedback on the two diagram, I'm not an expert when it comes to the airflow.

Thanks.