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7800 GTX Cooling Mod - also in second slot

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You can read here:

http://www.dfi-street.com/forum/showthread.php?t=22178

Why I moved my video card down to the second slot, and the results I achieved by doing so. Summary (lowered chipset and cpu temps, created more space for HD)

 

I wanted to cool my BFG card. I noticed at stock it was running at 54C idle and 74C load. This seemed really high to me and MBM5 was throwing alarms with its default alarm settings.

 

 

After doing some quick research I noticed people achieved mix results(good and bad) with the Zalman 7000 CuAl. Plus, since I relocated my card to the bottom, I do not have clearance for the Zalman without losing my Audigy 2. I took the 70mm muffin fan off of the stock AMD heatsink. I screwed this fan into the heatsink on my BFG 7800 GTX. See attached pictures.

 

First Picture: My slot configuration

Second Picture: My video card quick fan mod

 

Now it is running at 46C idle and 54C load.

 

Problem: This fan has a thermistor on it, and it thinks it needs to operate in temperatures corresponding to an Athlon64. As a result, it thinks its too hot and runs at full RPM all of the time. WHIRRRRRRRRRRRR It is loud!

I need to A) disable the thermistor and control the fan with my Hardcano fan controller or B) find another suitable fan that does not have a temperature regulating thermistor. Anything bigger than 70mm is too big. Some have tried with the 80mm, but the hub is just too big... creates a hot spot in the middle.

 

Hope this helps ppl get some ideas, because I've seen a lot of people ask the questions.

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Ok, I was not satisfied with the noise. So I changed out the fan to one that does not have an integrated thermistor. [Got this from an old Athlon XP cooler]

 

vid18zu.jpg

 

I was concerned about taking the shroud completely off. I did some measuring, and came up with an idea to make an effort to replace some of the shroud.

 

vid20rb.jpg

 

I took the blister pack from my RAM and made a custom shroud.

 

vid39mf.jpg

 

vid41rm.jpg

 

vid50rr.jpg

 

The desired product is in the lower right.

 

vid63dn.jpg

 

I made the screw holes by poking with a large safety pin, then I used a pointed woodscrew to ream the holes a little larger. I pre-screwed the screws into the shroud to make it easier to assemble.

 

vid79pl.jpg

 

vid81tw.jpg

 

Here is a shot of the testing with the fan controller.

 

vid95ya.jpg

 

Here you can see the clearance, it is in close proximity to the audio card, but it seems to be ok.

 

vid107bg.jpg

 

 

Testing and results.

Ok, stock fan, heatsink, no fan controller.

Idle 54 / load 74

 

Fan at max speed, no custom shroud, no fan controller (This is really loud. WHIRRR)

Idle 47 / load 54

 

Fan at max speed, with custom shroud, no fan controller

Idle 47 / load 54

 

Fan with custom shroud at low speed on the fan controller (~3000 RPM - very quiet/inaudible)

Idle 54 / load 62

 

Fan turned off with custom shroud in place (this simulates fan or fan controller failure and relies on stock fan with custom shroud only)

Idle 59 / load 76

 

Conclusions:

1) The stock cooling solution lets this thing run pretty warm ~75 degrees with load.

2) With the little fan I added running at max speed ~5000 RPM or more, it is loud. The custom shroud has no effect at all under these conditions.

3) Using a fan controller to drop the fan speed to ~3000 RPM made it much more pleasant to be around (inaudible). The temperatures are still ~10 degrees lower than stock. Because of this, I consider the mod a success.

4) I was concerned what would happen in the event my add-on fan failed, or my fan controller failed. (More likely the fan becoming unplugged while mucking around in the case). With the add-on fan powerless, and the custom shroud in place I achieved acceptible results. I can feel fairly safe that if I experience an undetected failure with my customized fan, the stock fan will sufficiently cool the card, even under load. This makes me feel more comfortable with the mod.

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I wonder when someone will come up with a decent 3rd party kit that pulls the air out through the PCI brackets below the cards! Id use them with my 7800s in SLI!, if they designed it reasonably well there should be enough clearance for the airflow too. Hope Artic Cooling get on this quick!

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I wonder when someone will come up with a decent 3rd party kit that pulls the air out through the PCI brackets below the cards! Id use them with my 7800s in SLI!, if they designed it reasonably well there should be enough clearance for the airflow too. Hope Artic Cooling get on this quick!

 

They have a bew version of the nv5 silencer coming out soon what wll supprt the 7800 series of cards.....ASUS alreadys uses it on their top o' the line model. Unfortunately, I doubt they have changed the design that much because in previous revisions the fan stuck out too far for you to be ale to use two of them in SLI....

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