Modifying the stock AMD heatsink fan

Rebellious · Post by **Rebellious** » Thu Dec 27, 2007 6:21 am

It's the retail version for AMD Athlon 64 X2 Dual-Core 6000+ 3.0 GHz 125W

It's well matched to the processor and cools very well, but it's NOISY. I wonder if it can be modified by replacing the 70mm fan with 120mm.

The fan clips on with 4 tabs. The idea is to gut the fan but keep the clip-on frame to which you attach a 70mm to 120mm fan adapter --

http://www.svc.com/fa70120-uvblu.html

Something like this

I'm just not sure if the plastic air cowling is designed to hold the extra weight. Has anybody done something similar?

...

Rebellious · Post by **Rebellious** » Thu Dec 27, 2007 6:44 am

BTW, this HSF is manufactured for AMD by AVC. AVC also makes the stock HSF for Hewlett Packard. Here is a review

http://www.frostytech.com/articleview.c ... cleID=1962

And a comparison of the original design to Thermalright XP-90

http://www.madshrimps.be/?action=getart ... rticID=399

. . . that was reviewed here on SPCR

http://www.silentpcreview.com/article194-page1.html

thejamppa · Post by **thejamppa** » Thu Dec 27, 2007 7:02 am

Its Doable. You need to remove the plastic casing around the fan aswell. Then you can fit 120mm->80mm Adapter there. You may need to modify the adapter though.

Some peoples attach that thing with grazy glue others use other methods like zip ties etc.

Since adapter has a funnel, yourr best option would be to modify somehow so that the funnel is as close the center of HSF so that there wouldn't be left big exposed area between afapter and HSF. Some peoples use stiff material like thick cardboard to make duct.

You could try your self building duct aswell. Some peoples have ducted 120mm fan to cool Slot 1 P3's ( which originally had 40mm fan ). All you need to do is use imaginetion and look ducts what peoples have made. Bluefront is very creative when it comes to ducts.

dhanson865 · Post by **dhanson865** » Thu Dec 27, 2007 9:28 am

Why not jut lay a 92mm fan directly on top of the HS without an adapter and fix it in place with zip ties or something?

You have to consider that fan adapters that funnel the air increase resistance and increase the noise of the fan so using a 120mm fan with an adapter won't necessarily be quieter than a 92mm fan with no adapter.

Rebellious · Post by **Rebellious** » Thu Dec 27, 2007 10:26 am

It would be hard to reproduce the turbine effect of the original design. The stock design creates air pressure inside the heatsink, just like the Porsche air-cooled engines. Air is exhausted from 2 sides, cooling the mobo. It looks optimized for low turbulence, but whistles when ramping up/down, like a turbine. The whistling is probably due to poor airflow under the center hub/motor, forcing air through the slot of the AM2 clamp.

The heatsink is not flat on top, it's a stair-step design (U-shaped north/south, so the purpose for the adapter is to funnel air to the core of the heatsink, otherwise it will blow out from the sides.

(photo from Frosty's review above post)

To stock HS is very adequate, so I want to avoid replacing it with a large Ninja-type HS because these cannot be serviced without removing the mobo. Also large passive heatsinks are too heavy in my opinion, especially when cantilevered with 120mm fans, vibrations, high maintenance, etc. But I may go that way if a simple fan replacement doesn't work.

dhanson865 · Post by **dhanson865** » Thu Dec 27, 2007 6:20 pm

I understood the design before you replied. I still think I'd try a 92mm fan on top before I got much fancier. I don't know about you but I'd borrow an intake fan off a Solo or use a spare 120mm fan I have laying around to see how well the concept worked. If you don't have a fan laying around that you can test with I can see being more reluctant to try.

I would use the Scythe 92mm Case Fan - DFS922512L 2000 RPM at 12v but use speedfan to lower the RPMs as far as I could. Of course that fan has been out of stock on Jab-tech for a long time so you may not be able to find one.

YATE LOON 92mm Case Fan - D90BM-12 is in stock and is even cheaper. It's 2300 RPM at 12v but again I'd speedfan it down a chunk. If you prefer to hard wire the fan it is rated to work down to 6.5v so 7v fixed would work no problem and 5v might work depending on luck of the draw. And you can get them as cheap as $3.50 + S&H.

Your HS is one of the AVCs below. All of my AMD CPUs have come with the Ajigo instead.

Code: Select all

Heatsink/Fan                                            Noise Fan V  Â°C Rise Â°C/W MP Weight
Ajigo MF064-074 (70mm fan no pipes)               ($ 5) ??    ?      ??      0.??    373 (363+fan)
AVC Z7U7414001 (70mm 4 heat pipes)                ($10) ??    ?      ??      0.??    440
AVC Z7U7414002 (70mm 4 heat pipes)                ($10) ??    ?      ??      0.??    440

If you want to keep the weight down and get a new cooler you could consider

Heatsinks Compared at ~23 dBA@1m:

Code: Select all

Heatsink/Fan                             Noise Fan V  Â°C Rise Â°C/W MP Height Weight
Asus Triton 75, Nexus 120         ($45)  23   12      18      0.24    90/115 473* (350+fan)
Thermalright XP-120, Nexus 120    ($??)  23   12      25      0.32    63/88  493* (370+fan)
Thermalright SI-120, Nexus 120    ($??)  23   12      ??      0.??    90/115 523* (400+fan)
Thermalright SI-128, Nexus 120    ($45)  23   12      21      0.27    92/117 633* (510+fan)
Thermalright SI-128 SE, Nexus 120 ($60)  23   12      ??      0.??    92/117 633* (510+fan)
Scythe Andy with stock fan        ($45)  20   12      16      0.21   100/125 685  (???+fan)

Scythe Ninja Mini, stock fan      ($40)  28   12      19      0.24     115   678* (580+fan)
Scythe Ninja Mini, Nexus 92       ($??)  20   12      ??      0.??     115   678* (580+fan)
Scythe Ninja Mini, 92mm fan ~23dBA($??)  23   12      ??      0.??     115   678* (580+fan)

Height is heatsink/combined height or if centered the fan doesn't add to height. For the ones with a / you will want an additional 25mm or greater clearance for airflow.

* http://www.nexustek.nl/120mmcasefan.htm lists the Nexus 120mm fan at 123g
http://www.nexustek.nl/92mm_real_silent_case_fan.htm lists 98.5g
http://www.nexustek.nl/80mmcasefan.htm lists 85g

If you already have a 92mm fan laying around the Ninja Mini has promise as a good choice. If you don't the Scythe Andy comes with a fan that is worth using. If you are really adverse to the weight you could consider the Asus Triton 75 it doesn't cool as well as the Andy but it's lighter by a noticeable amount.

Since I'm in the US I just grab sleeve bearing fans by Scythe or Yate Loon that are nearest the rpm of a Nexus and I usually do so buy buying a few at a time from sites that sell them around $2-6 each plus S&H.

120mm Nexus = 1000 RPM
92mm Nexus = 1300 RPM
80mm Nexus = 1500 RPM

fwiw the 70mm stock fan on my Ajigo is running at about 1300 rpm as I write this simply because the motherboard I'm using it on won't let it spin down as far as I like. On other motherboards I've had it under 600 rpm with speedfan. The 12v speed on that fan is 3000 RPM so it isn't unreasonable to assume that you can slow a fan down to 1/3 or 1/5 of its max speed without spending money on a fan controller.

jaganath · Post by **jaganath** » Thu Dec 27, 2007 6:23 pm

It would be hard to reproduce the turbine effect of the original design. The stock design creates air pressure inside the heatsink, just like the Porsche air-cooled engines.

what turbine effect? axial fans, especially small ones, do not create much static pressure at all. also I do not see any turbulence-reducing features.

Rebellious · Post by **Rebellious** » Fri Dec 28, 2007 6:07 am

Thank you, this is very helpful. There are probably millions of users with 125W processors. It would be nice to find an inexpensive solution to this, short of replacing the entire HSF because all it needs is a quieter fan.

I'll try whatever works, and I'll be back with more photos

...

dhanson865 · Post by **dhanson865** » Sat Dec 29, 2007 9:01 am

viewtopic.php?p=385378&highlight=#385378

two of the reviewers on newegg actually used the mini to cool a 125W TDP FX-62.
125W TDP!

Not only did it cool it, but they bragged about how it cooled so much better than the 4 heatpipe heatsink that AMD provides (which has a 5000 rpm thermally adjusted fan).

This cools VERY well. Dropped temperatures from stock 4 pipe AMD cooler: (full load) 54c to 46c (idle) 42c to 34c With the stock 80mm fan.

If the stock fan on the Ninja Mini were a 92mm fan that runs under 2000 rpm at 12v (and would start at 5v reliably so we could run it at 5v fixed) it would have been the perfect mid range cooler.

As is I hope your AVC cooler works out better for you with a 92mm fan on it

Greg F. · Post by **Greg F.** » Sat Dec 29, 2007 11:49 am

I used that exact adapter on a old AMD X1800. I never had to remove anything from around the heatsink. I just screwed the adapter in place of the stock fan and then screwed the bigger fan into the adapter. four screws, easy. No extra weight to speak of. It was subjectively much quieter for me.

Modifying the stock AMD heatsink fan

Modifying the stock AMD heatsink fan

Used that