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Discussion Starter #1
I did a little mod on the stock cooler aiming to improve VRM cooling using spare junk, but forgot to take the temps before I modded it. I need to know the VRM temps of people who have not modded the heatsink to compare my results, but I have seen a few on the internet and found that my results are pretty good.

First of all, my results. VRM temps max out at 90C. The card is overclocked to 850/1000 @ 1.33v, and ambient temps are ~30C.



Compared to a stock 4870 Toxic, and water cooling.

Here's what I did. This is assuming you have a reference 4870 PCB and heatsink:


... an old AM2 CPU heatsink (or similar, you just need fins of the same thickness):


... and finally, some TIM of your choice, preferably non-electrically conductive.

1. Remove stock cooler

2. Clean up. That thin strip of I-don't-know-what is used to fill the air gap between the VRMs and the heatsink, but it barely does its job. Remove it, we will replace it with something better.


3. Cut 2 strips of aluminum from the AM2 heatsink, enough to cover the VRMs. I just bent some fins and used a pair of scissors to cut the strips, but you might have better cutting tools available to you. Be sure that the strips are flat, otherwise pound them flat against a table using the bottom of the AM2 heatsink or something.


4. Apply TIM on each VRM. Place the 2 aluminum strips over the VRMs. Apply TIM on the surface of the aluminum strips and the GPU.

5. Finally, reseat the heatsink. Be careful not to slide the aluminum strips from their positions.

6. ???

7. PROFIT!

I used a stock AM2 heatsink to make the strips because I had one lying around, and the fins looked to be around the thickness of the gap between the heatsink and VRMs on my card. When I placed the aluminum strips without TIM and screwed the heatsink on to test, the strips stayed in place, confirming that there was enough contact and pressure between the heatsink, aluminum strips, and VRMs. There are better alternatives to aluminum strips, such as copper, but I don't have any available with me.

By looking at pics of other reference coolers/PCBs, it looks like the mod is doable on other cards as well (such as the 4850, 5870, and maybe even some Nvidia cards). For the price and effort required, I love the results and will definitely try this mod again on my next card.
 

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Very creative, never thought about that!
 

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Discussion Starter #6
Pics of mine with the TIM cleaned off.



Quote:

Originally Posted by Rewindlabs View Post
How are you sure Furmark is not throttling?

For the life of me i can't be sure it is or isn't..
I renamed FurMark to etqw.exe, so the throttling wouldn't engage.
LL
 
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