My 4870x2 fan mod w/pics

I hate a loud computer, so I replaced the stock fan on my 4870x2 with a 120mm, and I'm using a fan header on my Abit mobo to control it. Result is that at gpu clk = 800 Mhz, 30 minutes into crysis I can just barely hear the fan at all...with speakers turned off! I am absolutely shocked that this works so well, the fan is turning at about 1000RPM with no artifacts/crashing/high temps while in the heaviest games. The key is that ATI left the top of the HS open so that the air from my 120mm blows straight down into/between the HS fins. Before this mod, the stock fan was earsplitting. And the best part is that the second I get out of the game, the RPM drops to 600 RPM cause it's controlled by the mobo header which is referenced to CPU temp, not sys temp. So on desktop, it's like "is this thing even running?"

Even if you have a non-Abit mobo, you can still reference CPU temp by piggy-backing the vid card fan on the CPU header, just make sure you have a PWM fan, not a DC fan.

I tried this same mod on the gtx280 I used to have, didn't work nearly as well due to the ineffectiveness of the nvidia HS.

Temps ?

Congrats, but I really don't find my 4870x2 to be "earsplitting" even under heavy load. Sure I can hear the fan running, but it's certainly not terrible by any means.

Yup, I'd love to see the temps, the turbine fans of ati are good .. suck cold air blow it with high speed and pressure through the GPU fins and blow it out of the case. How are the VRM and DDR temps ? The technology of G Turbine fans is good the problem is the noise if you're not used to it. But one low RPM fan blowing directly on two R4870 GPU's ? If that was a 2000 RPM Sytche I'd probably say It's okay but 600 RPM ? Show us the temps :p: and in Furmark too [ If you're using 8.8 Drivers rename the furmark.exe for something else so the driver doesn't triger the Furmark low heat profile ]

Could you do a "How-to" for this?

Also, any reason why you didn't use Yate Loons?

Perkam

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Originally Posted by perkam

Could you do a "How-to" for this?

Also, any reason why you didn't use Yate Loons?

Perkam

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I believe he just simple removed the plastic housing that houses the fan. and put a 120mm right over the copper blocks of the gpu's. The only thing I forsee with this is no real good cooling for the VRM's. I guess if you really wanted too you could cut the stock housing and mount the 120mm inside somehow. But temps on this would be interesting.

First, some system notes:
1. I have no side cover on my case, and no case fans.

2. Exactly three fans total...PSU, CPU, vid card all 120mm. I did the same mod to my PSU, that is, I replaced the stock 120 fan with a 4 wire PWM 120 and ran the cable to my CPU header and piggybacked it with my 120mm PWM CPU fan.

3. I've created a fan profile in BIOS that results in Desktop 550/550/900 RPM for my PSU/CPU/vid card. In games I'm 650/650/1200 RPM.

4. The 120mm is tall enough so that the air stream blows directly on the the upper black HS of the vid card.

For testing, I ran ATI tool for 45 minutes, no errors, temp stablized at 77C. Next, I launched Crysis and went to an area where I wouldn't die. I came back one hour later, and played for another five minutes or so. All this time, no artifacts, lockups, etc. 100% normal function. Upon exit to desktop, Control center temp read 87C, which quickly dropped to 51C. Fan RPM dropped to 900 in less than two seconds upon exit. I also ran 3DM Vantage, between screen loads I was seeing low 60's temps.

Quote:

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Originally Posted by perkam

Could you do a "How-to" for this?

Also, any reason why you didn't use Yate Loons?

Perkam

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Unlike with a gtx280, the 4870x2 is a piece of cake cause it just uses screws to secure the plastic shroud. Just start on the back plate and remove any screw you see, eventually you'll have it apart. After I got all visible screws out, it still wouldn't come apart. I gently lifted each of the white HS material until I found that one of the pads was covering the last screw. After removing, I reattached the two HS and backplate. Only thing to be aware of is that all screws are Philips, and of two sizes. The larger ones can be turned with a common small screwdriver, but you probably won't have a small enough head for the smaller screws. I just used the tip of a kitchen knife, they came out easy since they weren't torqued tightly.

As to Yates Loons, any 3 wire fan will work, I'd recommend either 120 or 140MM so the black HS is cooled. IN fact, a 140mm would probably work even better, but I didn't bother because the 120MM I had lying worked just fine.
Key is that you must use a three wire so that you can have fan speed thermally controlled by the aux fan header of your mobo so that you have low speed when in desktop. Ideally you want an Abit mobo so you can use a 3 wire DC fan. If you are using a non-Abit board, you'll need to use a PWM fan and piggyback of the CPU header. This results in going from game RPM to desktop RPM immediately.

you might even consider using an 80mm fan on your g-card instead lf a 120mm one. since the fan is touching the heatsink, there is a dead spot around the fan's center hub. much of its airflow is pushed outward instead of just going straight forward. having too big a fan can be counterproductive in this case.