Modifying the EVGA ACX cooler

Unknown-One

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Figured this mod was worth mentioning here, as I'm rather pleased with the results.

This all started because of a bad run of ACX coolers that all had whiny fans. You can read about my trip through RMA-hell right over here: http://hardforum.com/showthread.php?t=1801784


Supplies needed for this mod:
1. EVGA ACX cooler (GTX 780 / GTX Titan variant)
2. Two Arctic F9 PWM fans
3. One PWM fan adapter
4. Two small squares of 3M double-sided foam tape.
5. A pile of zip-ties
6. A pair of pliers and a small file
7. Small screwdriver set
8. Soldering iron, solder, shrink tubing
9. A clip-on ferrite core


Here's what we're going for when we're all done...
Off the card, ready to mount:


On the card, ready to be fired up for the first time:



I didn't take photos of the build process, but here's the gist of it:
1. Remove the ACX cooler from the graphics card
- Doing this requires removing 4 spring-loaded screws on the back of the card, around the GPU.

2. Remove the fan shroud from the ACX cooler
- You'll find two screws on the underside and one screw on either side of the shroud.

3. Remove the stock fans from the ACX cooler
- Three small screws on each one. You'll need to get a jewelers screwdriver between the blades

4. Place the new 92mm fans on the cooler
- One fan will need to have two small chunks taken out its frame to clear some small threaded post-holes on the cooler. I just used pliers to snap off the pieces.
- A metal tab (formerly used for cable management) needs to be bent vertical.
- Two squares of foam tape are needed to make the second fan mount level.

5. Wire up the fans
- These fans include PWM-sharing. Simply chain the connectors together and connect the terminator from one of the fans to the end of the chain.
- Use the adapter to connect the fans to the card's fan header. Speed control will work as per usual.
- If you experience your fans ramping-up to full speed at random intervals, you need to shorten your fan cables. Break out the solder and shrink tubing!
- Additionally, clip one of the ferrites (linked above) onto the yellow RPM-sense wire. This effectively creates a simple low-pass filter that will help strip a lot of RF-noise from the RPM signal.

6. Get creative with zip-ties
- You'll only be able to mount the fans corner-to-corner. It took a while to figure out the best and cleanest way to do this.
- Cable management can all be done on the motherboard-facing side of the cooler.
- Avoid having any cables come in direct contact with the heatsink fins. Melted cables are bad! This is possible (none of my wires touch).
- If you do find that you need to have wires in direct contact with the heatsink, make sure to wrap them in shrink tubing (the stock fans use this method).

7. Install and enjoy
- Remember to set a custom fan profile. Mine run at minimum speed until 40c, then go through an exponential ramp to 100%.
- Temps should be ~29c idle, 72c load
- Noise levels should be reduced to almost nothing!


Updates:
Edit 1: As an added bonus, this also gives you slightly more breathing room as far as power-target goes. The stock EVGA fans draw over 13 watts when running full-speed, while these Arctic F9's draw a total of 3.6 watts combined! This difference is actually noticeable, and could allow slightly better overclocks on an unmodified BIOS.

Edit 2: I discovered that enough RF noise can accumulate on the fan RPM sense wire (the yellow wire) that it causes the GPU BIOS to detect a fault condition. When this happens, the fan ramps up-and-down continuously as the video BIOS tries to restore sanity. I had to shorten the cables as much as possible AND add a clip-on ferrite core in order to totally eliminate spikes on the RPM sense wire. Shortening should be done using solder and shrink tubing (which I've added to the parts-list above).

Edit3: Just some additional information. The best way to troubleshoot the fan speed issue is to install EVGA Precision and set the polling interval to 100ms (fastest polling interval allowed). This will allow you to monitor spikes on the Fan Tachometer graph in real time (spikes you can't see with the default 5000ms polling rate). Ideally, you want to see NO spikes on this graph, because enough spikes will trigger a fault condition and the GPU BIOS will force the fan up to 100% temporarily to try and resolve it.
 
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FnordMan

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Nice! I especially like step 6.
Plus it's only a tiny bit thicker than the stock one.
 

tommye

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Jun 29, 2011
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Yes! This is exactly what I'm looking for. I was contemplating drafting a plan to solve this problem tomorrow but it looks like you've basically done the basic groundwork. I've also been through RMA hell and every single damned time has resulted in a fan that has an annoying grinding sound.

Regarding step 5, I'm assuming you solder the wires from one of the fans to the other?

Edit: I'm overthinking it, you can just an adapter.
 
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Unknown-One

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I would like to note that I did end up shortening the fan cables to sort-out an annoying issue with auto-fan-speed.

I noticed that my fans would randomly ramp up to 100% fan speed all on their own, over and over. A quick look at EVGA Precision's fan speed monitoring showed that I was getting all kinds of spikes and dips in the "Fan Tachometer" graph. The video BIOS detects these spikes as fan faults, and immediately ramps the fan up to 100% speed in an attempt to restore sanity (100% fan speed is effectively a fail-safe).

I had originally kept the full length of the fan cables, wound them up, and zip tied them. All that cable was sitting sandwiched between the graphics card and the motherboard, which is apparently a happy-fun-EM-playground. There was enough ambient electromagnetic noise that the fan RPM sense wire was picking it up and sending it along to the graphics card, causing the crazy RPM readings.

Shortening the fan cables (with solder and shrink-tubing) down to a more manageable size immediately cleaned up the problem. Also made for a LOT less wire to zip-tie :p

I would probably have to shield the cables, or add a ferrite core, in order to eliminate 100% of the noise on the line. I still see a spike or two every once in a while, but it doesn't seem to be enough to trigger a fault condition anymore. Auto-fan-speed now operates as expected.
 

D4rkn3ss

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never thought of using ferrite cores for stuff like this.. well, everyday you learn something new, nice job man.
 

ep0x73

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9/10

Now slap on a pair of these and let me know if it flies.
Personally I'd go with Noctua fans, the very best CFM/DB right now.
Still very crafty on your part.

Tornado, yeah I have a 80mm sitting in a junk drawer from many years ago.

That baby can take your finger clean off and it sounds like a hoover!
 
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Don't you just love holding it in your hand and pretending it's some sort of space gyroscope of doom!
 

Unknown-One

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never thought of using ferrite cores for stuff like this.. well, everyday you learn something new, nice job man.
It's a bit of an odd use, I'll admit. It did a perfect job cleaning up the strange tachometer readings I was seeing, though :p

Adding a ferrite to a wire effectively creates a simple low-pass filter. High-frequency noise is absorbed by the ferrite and converted into a small amount of heat. The RPM signal from the fan (the signal we actually want to keep) is relatively low-frequency, so the ferrite leaves it alone.

Edit: Heh, so apparently, people who have attempted to use Arctic Cooling heatsinks (like the Accelero eXtreme III) on the GTX 780 have also run into the fan-ramp issue. I wonder if shortening the fan cable and adding a ferrite (or shielding the cable) would solve the problem for them as well.
 
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ep0x73

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Don't you just love holding it in your hand and pretending it's some sort of space gyroscope of doom!
LOL, yeah but hold on tight and carefully or you might see red on your walls.

Massive force for such a small fan, I can only imagine if they ever made a 120mm.

85 CFM with 55db for the 80.

I thought it would be neat but after awhile I could no longer handle the noise.
 

D4rkn3ss

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It's a bit of an odd use, I'll admit. It did a perfect job cleaning up the strange tachometer readings I was seeing, though :p

Adding a ferrite to a wire effectively creates a simple low-pass filter. High-frequency noise is absorbed by the ferrite and converted into a small amount of heat. The RPM signal from the fan (the signal we actually want to keep) is relatively low-frequency, so the ferrite leaves it alone.

Edit: Heh, so apparently, people who have attempted to use Arctic Cooling heatsinks (like the Accelero eXtreme III) on the GTX 780 have also run into the fan-ramp issue. I wonder if shortening the fan cable and adding a ferrite (or shielding the cable) would solve the problem for them as well.
a few years ago i got a few of those clip-on ferrite cores to damp the interference i was getting on some ac-dc converters, it was a tip from a friend who works with electronic stuff and it worked, i ended up forgetting about them, never thought of using them on other applications, you gave me a few ideas :D

yeah, it could be related to arctic cooling fans. ever thought of trying noctua fans? theyre so good man, i think those slim nf-a9x14 would fit pretty well
 

angel_grin

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Apr 11, 2014
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nice mod, i've been thinking about this for a few weeks now. and i stumbled upon your thread!

does this void the warranty?
 

Unknown-One

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does this void the warranty?
Not if you're careful. You can literally bend one metal tab back into place and re-install the stock fans and fan-shroud like nothing was ever modified.

If you do somehow manage to damage your ACX, you can buy a new ACX cooler from EVGA for $40. Not a huge risk, really.
 

donchill

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the expectation was big when i got my RMA card (evga gtx 760 SC ACX) from my old evga gtx 570. (lasting about 3.5 years oc'd)
as soon as i fired it up i noticed this very annoying grinding noise, even the fix with putting thermal tape on the metal fins didnt pleasure me. then i found your thread
this sound https://www.youtube.com/watch?v=DAD4fA0RF2Y

i did about the same except i got noctua nf-a9 92mm pwm fans which are nearly the same as the arctic ones http://noctua.at/pdf/infosheets/noctua_nf_a9_pwm_datasheet_en.pdf

the part with "get creative with zip ties" was a pain, but i still managed to do it
one metal bracket at the end of the cooler had to be removed, otherwise the fan wouldnt fit in

some pics:

http://i.imgur.com/0uQiYRR.jpg

http://i.imgur.com/y5tb3kf.jpg?1

http://i.imgur.com/PDbP3JB.jpg

http://i.imgur.com/3akFIen.jpg?1

i never had that pwm fan issue, but i still just clipped a ferrit core over the fan cables (two in total)

http://i.imgur.com/3o1FBoK.jpg?1

idle: 29-32°C
black ops 2 multiplayer: 58-73°C (room temp 22°C) depending on map

stressing with msi kombuster fired up to 90°C, (1241MHz) then it started to clock down to 1188)
but this test is too unrealisitc, i will test soon with crysis warhead


i will still get evga cause of their warranty support, but probably never again a ACX cooler, maybe i switch to asus or msi

cheers for that guide
 
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doyll

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I have done this a few times with 120mm fans with good results. The extra airflow around & through fins between 120mm and 92mm fans adds cooling not just to cooler, but to other components on PCB.

Don't want to bother with wiring PWM speed control? The F12 (& F9) TC have speed control built in using a remote sensor. Plug them into powr and slip the sensor into heated exhaust airflow and idle up to about 30c, then ramp up as temp increases with full speed at 38c air temp.

Nicest fans I've used are Thermalright TY-100 At 108x101x14 mm in size with 900-2500rpm PWM control makes them a natural. Problem is they are not sold individually. I did a couple of custom build that owners wanted 120mm fans on their AXP-100 cooler and ended up with the TY-100s. :D
 
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