Extra Cooling for 6600 GT

anandtechrocks

Senior member
Dec 7, 2004
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I've been increasing the speed of my 6600 GT and decided to also increase the cooling. I got a Panaflo fan I had lying around and it mounted to the bottom of my case. I can't find my digital camera USB cable so I "Painted" it:

Extra Cooling Picture

For some reason my tems went up 1C during load! I know it is just 1C but does something about this setup not make sense? As you can see by the drawing the GFX card fan is blowing hot air away from the core and then the 92mm fan blows the hot air out of the case. I have removed all of the PCI panels.

I was hoping to lose some heat not stay the same or increase (even if it's only 1C).

Thanks for any ideas.
 

GalvanizedYankee

Diamond Member
Oct 27, 2003
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I just bumped it as you signed off.
Search, Easy 7800 GTX Cooling Mod 38C on air at idle! Read it. Good thread.

Galvanized
 

anandtechrocks

Senior member
Dec 7, 2004
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Actually, this setup is very similar to the 7800 GTX Cooling Mod, and I'm sure the fan on the bottom is pulling hot air away from the HS. Any other ideas?
 

zagood

Diamond Member
Mar 28, 2005
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Just removing the PCI shields is the cause of the heatup. If you added a fan to blow out where that open space is, then it would work better. What's happening is that some hot air is getting out of the case, but so is the cool air that you're sucking in with the 92mm panaflo. Remember, heat rises.

The most efficient way to air cool with standard cases is a fan (or fans) blowing in from the bottom front, and a fan (or fans) blowing out from the top back or top of the case. That way you have a steady flow going.

Read this thread

Also, the heatsink fan on your vga card is blowing air toward the heatsink. It just seems like it's sucking away since it blows back off the card.

-z
 

anandtechrocks

Senior member
Dec 7, 2004
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Hey, thanks a lot for the information zagood! Ok so would this setup be better?

Different Fan Positioning

(PCI slot covers are removed, and 92 mm fan is exausting the hot air.)

And by the way, I'm positive that the fan on the GFX card is blowing hot air away from the HS because I installed it myself.
 

zagood

Diamond Member
Mar 28, 2005
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You should really consider disassamble and re-install the HSF with the air blowing toward the heatsink. What heatsink are you using? Stock? Aftermarket? McGuyver?

That setup would work in theory, it'll be loud though (the air blowing off the metal between the slot shields). If you want to go with a setup like that, you should invest in a NV Silencer link as your heatsink setup (fan blows hot air through the heatsink out of a PCI slot opening) or a slot fan link would work as well.

-z
 

JEDIYoda

Lifer
Jul 13, 2005
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Lets talk about fan placement.....

if you are going to place an exhaust fan in open (reomved) PCI slots thats a good possibility....yet you can`t use any of those PCI slots.

With that said....

theres any number of possibilities....

you could get a self enclosed videocard cooler that uses just one additional PCI slot to exhaust the VID card hot air out the rear....

You could also fabricate a bracket or even buy a twin fan set up that would blow additional air onto your video card.

All the zalman video card collers draw air into the video card....
None of them draw the hot air away!!

Just a note,,,many people have stated on these and other forums that to have an additional exhaust fan on top of the case shows little or no effect on over all temps!
Yet haveing another fan blowing air into the case is not a bad idea!

I have blocked my top of the case opening for a fan!!

I am running real low temps for air cooling!!
 

anandtechrocks

Senior member
Dec 7, 2004
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Ok looks like this idea of mine isn't too great. I think I will switch the fan on the GFX heatsink to blowing onto the card, and install an old Vantec spectrum fan I've got. Oh well, I thougth this might be a good set up but, I guess not.

Hey, and by the way, anyone know how to disable the annoying leds on this thing?
 

zagood

Diamond Member
Mar 28, 2005
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Originally posted by: anandtechrocks
Ok looks like this idea of mine isn't too great. I think I will switch the fan on the GFX heatsink to blowing onto the card, and install an old Vantec spectrum fan I've got. Oh well, I thougth this might be a good set up but, I guess not.

Hey, if you've got time on your hands give it a try, you never know. Sometimes random results laugh at logic.

Try switching the heatsink fan and see how that works out. Plug up those PCI slots and focus on getting a smooth airflow from the front bottom to the top back of the case. If you get your case ambient temps down, your component temps will drop too.

What's your current case fan setup?

-z
 

zagood

Diamond Member
Mar 28, 2005
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Whoa. You sure do!

You've got a major positive pressure setup, that might actually make your case hotter. You should have about the same exhaust fans as intake fans, a little more intake is OK but you're going crazy man!

Remember your PSU probably has an exhaust fan too...

Is the 92mm next to the XP90 for cooling ram?

Is the 80mm intake at the top for cooling hard drives?

I'd really recommend either removing the 80mm intake at the top or if it's for HD cooling, lower the RPMs considerably.

Why do you have 2 80mm fans on your VGA card? I would think the one on top isn't going to do much except create turbulence. Hot air rises, you don't need to blow it from there.

JediYoda might argue with me, but you might benefit from a blowhole (exhaust) on top of your case. If only to even out the positive pressure.

-z
 

anandtechrocks

Senior member
Dec 7, 2004
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The 92 mm and the 80 mm at the top is for cooling the ram and the mosfet. The 92 mm pulls the hot air up and the 80 mm blows it away.

My PSU has a 120 mm exaust, and the main rear exaust fan has considerably more CFM than all the intakes combined. That way the pressure in the case keeps dust out.

The video card has a 3rd party heatsink and the 80 mm at the top cools the heatpipes.

Let me know what you think.
 

zagood

Diamond Member
Mar 28, 2005
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Ah, that's not bad at all if the rear has a high CFM, and if the VGA heatsink is heatpipes, well you're not going to do much more than you've already got.

It's a lot of fans, but it's not a bad setup. One thing you might want to consider is plugging the 80mm (edit...I meant 92mm) intake above the 120mm intake, and moving that fan to a side mount over the VGA, so you're blowing cool outside air directly on it.

And definitely switch the heatsink fan like we already talked about.

Allright man, off to bed, have fun and post some results...get your stock idle/load temps for CPU, VGA and Case recorded before you make any changes. Speedfan is pretty good for that if you don't have it already.

edit: Also set the ram/mosfet fan to blow AT the components you want cooled. That way it'll blow the cool air from the intake directly on the parts...more efficient than trying to draw hot air away. The only real way to pull hot air away from something is if you set up a duct...blowing air onto/across a heatsink or component is more effective.

-z
 

zagood

Diamond Member
Mar 28, 2005
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no problem. also take a look at my edits above.

You know, I just looked at your clock speeds for the first time...I really don't think you're going to get much more than that without water cooling or phase change. My 2c.

-z
 

2kfire

Senior member
Nov 26, 2004
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If you gained 1 degree by putting that fan there, just remove it! What are your current temps? With all those fans, you probably get pretty good temps as it is. My 6600GT gets up to 65 celsius max w/ a VF700CU. Maybe (like zagood said) you've reached your limit of air cooling and won't be able to get any better.
 

anandtechrocks

Senior member
Dec 7, 2004
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Here's the thing (my sig is a little out of date). I reseated the heatsink on my GPU and ever since then my overclock has gotten way weaker. I went from 595 MHz on the core and now I can only manage 580 MHz for some reason.

I thought it was because I changed some cooling configurations but I'm starting to think it has somthing to do with the core being chipped.

What do you think?
 

anandtechrocks

Senior member
Dec 7, 2004
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The graphics card temps are lower than ever, they hardly break 60C now (used to max out at 67C)! But my OC is still messed up! How did I lose 15 MHz on the core?

I reseated the HS again and 2 of the corners of the GPU are a little chipped, this is the only thing that seems to be different. Could this cause the decrease in my overclock?

Any ideas?
 

zagood

Diamond Member
Mar 28, 2005
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Pretty sure that's a thermal die, not the GPU itself that's chipped. Could have an effect but not 15mhz.

Considering the overclock you've had on that card, I think it's just getting tired bro. Might want to try burning in at the lowest BIOS voltage you can, that might bring back a little life but pretty doubtful.

-z
 

anandtechrocks

Senior member
Dec 7, 2004
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Alright, after reinstalling my GFX heatsink over 5 times here is what I concluded:

The heatsink I am using (Thermalright V1) is very difficult to install correctly. The heatsink must balance between two supports that are not mounted very well to the PCB.

After removing the heatsink I observed the thermal interface material and noticed that no pressure was being applied to the lower sections of the core. I remounted the heatsink and installed the lower screws with much more force than the top screws and I was able to gain my OC again!

However, with less pressure on the top portion my temps raised almost 7C! This has been a very tedious day and I'm almost ready to toss this V1 and get a Zalman VF700.

This GFX card is still not right, I just gave up for the day.
 

zagood

Diamond Member
Mar 28, 2005
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Ok, well, you've fallen into that strange realm where you have to weigh results vs. knowledge. Also, take into account the possibility that there may be other factors that are changing your results...amount of thermal grease, background apps at the time, etc.

What's more important to you...a stable overclock, or lower temperatures? That sounds like a ridiculous question but your results are outweighing logic.

The purpose of all this is to get a more stable overclock, right? If you can recreate the more pressure on lower screws/stable overclock, then stay with that (+7c).

You really have to weigh what's most important to you. Do some tests and ask yourself a few questions...

a) Does the overclock that you're attaining have any real world results? Are your FPS and/or image quality improved that much?

b) Are you willing to stick with the overclock results with the knowledge that higher heat over the long term will shorten the life span of your 6600GT? If you're thinking about buying a new vid card in the next year, it really shouldn't matter too much. You're taking a chance every time you reseat your HS that you're going to f up your vid card anyway, and an overclocker always has to have that in the back of his mind.

So anyway, if you really don't see much in the way of real world results, keep it the way it is. If you really want that overclock, just go with the higher temperature results.

It doesn't make sense sometimes, but if that's what you're experiencing, then weigh the options.

-z
 

anandtechrocks

Senior member
Dec 7, 2004
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Well, I lied I reset the heatsink 2 more times (I just can't sleep knowing my GFX card is messed) and I got it back to normal! And the temps are lower! I'm so happy. 595 core/ 1230 memory and the temps rarely break 62C! Thanks for all the help guys.

And as a side note I stand by my criticism of the Thermalright V1. The mounting brackets are not very good at all, pressing on one side of the HS creates a nice sized gap between the core and the HS! I'd definately go with the Zalman VF700.