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 Post subject: My approach to quieting a reference design ATI 4870
PostPosted: Sat Oct 25, 2008 11:02 am 
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Joined: Sun Jan 09, 2005 10:13 am
Posts: 17
Location: New Jersey, USA
I purchased a 1GB Sapphire ATI reference design 4870. I had read a few reviews and most said that it was quite quiet at idle. I would agree, but the card is biased toward silence at the expense of heat. At idle I was getting temperatures of around 80C. I had read that ATI has rated the GPU for 100C use so this is still within its design limitations, but a bit warm for my comfort.

The real problem, also noted in the reviews, is how quickly the noise ramps up when the card is under 3D loads. Wow! So based on both the high idle temperatures and the noise under load I decided to see what was available on the aftermarket. After doing a bit of research I settled on the Arctic Cooling Accelero TWIN TURBO as good solution. Warning - it takes three slots, which wasn’t a problem in my situation. One of the attractions for me in using this cooler was that the fans are PWM enabled and should work well with the built in fan controller on the video card.

http://www.arctic-cooling.com/vga2.php?idx=166

The problem is the voltage regulator sections or the VRMs. The Accelero TWIN TURBO includes some tiny heat sinks for the VRMs, but they don’t stand a chance of dissipating the heat the five VRMs put out. Fortunately from my research I knew enough to be careful about them and to monitor them. Unfortunately I didn’t know this about the TWIN TURBO before I installed it. So I went about looking on the internet for a solution to cool the VRMs and came across this thread

http://www.hardforum.com/showthread.php?t=1352018

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I wish I’d found it earlier because he had the identical problems that I did with the same reference design. So I’m going to shamelessly host his pictures and use them for illustration. By adding the TWIN TURBO to a reference design 4870 you are effectively creating a Force3D Radeon HD 4870 Black Edition without the factory overclock.

http://www.techspot.com/review/120-force3d-radeon-4870/

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The problem with the Force 3D is that in my opinion the small heatsink on VRMs is still inadequate for the card under load. There are many reports of 4850s and 4870s shutting down with the factory coolers on the current favorite benchmark / torture test FurMark.

http://www.ozone3d.net/benchmarks/fur/

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(In fact ATI added a profile in Catalyst on some cards to lower performance and heat specifically on FurMark. http://forums.techpowerup.com/showthread.php?t=69799)

Here are the VRM’s we are concerned about. They are the small chips grouped in three and two for a total of 5 chips. The group of three is next to the large rectangular chip labled VITEC.

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And here was Digital Viper-X’s solution – reuse the stock ATI VRM and memory heatsink. (He has RAM heat sinks on the some of the chips - it isn't required.) It’s worked very well for me as well. The VRMs are supposed to be rated to 125C and with FurMark running with the ATI heat sink I get temperatures in the 114C range. This is still hotter than I would like, but within specifications. Furthermore, no real world application has ever pushed these beyond 100C in my experience.

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The program you are going to want to grab to monitor all of you temperatures – three on the GPU plus three VRM temps is called GPU-Z. It is available here:

http://www.techpowerup.com/downloads/12 ... 0.2.8.html

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The next issue is that the built in fan controller didn’t want to work particularly well with the TWIN TURBO. This is the main reason I’m writing this up otherwise I’d simply point you to Digital Viper-X’s very complete post. The first problem was the issue that the fans wouldn’t move until the power level was 35% or so. At that point the first fan would come on, but not the second. At about 38% power the second fan would begin to turn. At that point the card would cool down enough so that the fan controller would shut the fans down. The card would quickly heat up with no fans running and the cycle would repeat about every 10 seconds or so. So I had the option of running manual control with a single speed or messing with the video card BIOS.

I’m not a huge fan of messing with a BIOS if everything is working. I’ve bricked a motherboard and been down for a week waiting for a new EEPROM. But I decided the risk was worth it in this case. Sadly as I feared while running about 10 iterations to try to find the best fan parameters I managed to lock up Vista 64 and brick my video card. I’ll spare you the two hours of finding an old 6600GT to boot the machine and recover the card. Let’s just say it is possible to recover your card. One of the reasons I bricked the card I think was because I got tired of rebooting after using multiple pieces of video monitoring software and I didn’t bother before the flash. So I suggest a reboot and closing every single program you can before the flash.

The program you are going to need is Radeon BIOS Editor or RBE.

*****Also if you are using a 4870 with GDDR5 DO NOT use ATI’s software either DOS or Windows based to EXTRACT the BIOS. It only saves 64k of the 128k BIOS. Use the BIOS extraction feature of GPU-Z.*****

http://www.techpowerup.com/downloads/12 ... v1.17.html

And here is a tutorial on how to use it.

http://www.techpowerup.com/articles/ove ... idcard/154

You are concerned only with the Fan Settings section.

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After lots of trial and error here are the setting that I found gave good results- Tmin 49, Tmax 85, Duty cycle 40. I left all of the other settings as per default on my card. If you have a different card they may be different.

(For reference the other settings are Use transfer function, hysteresis 0, Spin up cycle 84, Tmin hysteresis 4, Spin up time 4, PWM ramp on (is unchecked or OFF) and PWM ramp 0.)

I found that if I set the delta between Tmin and Tmax too big or set Tmin to 1 the card would let out an electronic whine. I think it’s the PWM fan controller, but I’m not sure. The only way to get it to stop was to set the fan speed to a manual. As I mentioned above between getting rid of the electronic squeal and getting a good curve on the fan I went through about 10 iterations. I’m hoping to save somebody the trouble. With the settings discussed above my card now idles at 51-53C with the VRMs at 65C. This is down from 81C idle and 90C or so on the VRMs.

The fan runs at 44% or so while the GPU is idle and is inaudible with my remaining system noise. At max load running FurMark the fan runs at 78-80% and is just above the noise floor of my system. The sound has no unpleasant tones to it. It is much, much quieter than the reference cooler under load.

Good luck and happy modding!


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 Post subject:
PostPosted: Mon Oct 27, 2008 7:12 am 
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Joined: Tue Sep 30, 2008 2:06 pm
Posts: 64
Location: MD
Tim, fantastic post! Thank you!


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