8800GTS cooling...improved....

T

TheRapture

Supreme [H]ardness
Joined
May 31, 2000
Messages
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I had seen something on this earlier, just never got around to it...but if you want better cooling without running the fan speed higher, then all you need to do is tape up or somehow cover the vents that are on the heatsink that face down, right at the back of the card right before the exhaust grill.. These vents, at low fan speeds, simply dump the hot exhaust air BACK INTO the case, actually, right into the intake for the video card. I was seeing 85c-87c load temps on my card at stock fan speeds (card over clocked of course) and was always cranking the fan speed up to 85% or even 100% for long sessions of gaming.

I took some clear scotch tape and covered the vents, and voila!!! Instant 5c minimum temp drop. Running a steady 80c right now at stock fan speeds, card at 600/1850, and a full screen session of RTHDRIBL. Pretty big difference considering how cheap it is. The scotch tape will be replaced with something more permanent soon, but try it, you will find it helps alot. Not to mention cpu temps will drop 1 or 2 degrees since it also is not being fed the hot video card air.
 
i'm not sure if that's good for your card

here are some other ways to cool it


slot fan
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custom vent w/ fan at the back
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thread 1

thread 2

another thread on the matter
 
This was tried months ago and most of us had a significant RAISE in idle and load temps.

Elmo has the right idea though - I bet the sales of slot blowers have increased quite a bit thanks to the G80 boards. :p

I've got a cheap Enermax blower under my 8800GTS and it works wonders.
 
If his card runs cooler, how can it be having a negative effect? Wouldn't that show up in the temps? Not saying your other methods wouldn't give a greater improvement, just that his seems to be safe given the results.
 
Blue Falcon said:
This was tried months ago and most of us had a significant RAISE in idle and load temps.
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I did not block off the rear grill.....just the one on the stock heatsink that vents INTO the interior of the case. Taping just those off will NOT increase idle temps. It's physically impossible, since you are directing MORE of the hot air outside of the case.

If someone got HIGHER temps by doing what I did, then they also did something else.....


Previously, at STOCK fan speeds, with the card OVERCLOCKED, it was idling at 63c-65c.....right now it is idling at 57c. Definitely NOT hotter. Somebody has some bad info.
 
TheRapture said:
Taping just those off will NOT increase idle temps. It's physically impossible, since you are directing MORE of the hot air outside of the case.

If someone got HIGHER temps by doing what I did, then they also did something else.....
Click to expand...

It's not physically impossible. Blocking off those vents will mean that the air has to travel further through the heatsink before getting out. Air has viscosity, so that increased length means more resistance to flow so air travels slower (given the pressure from the fan remains constant). Convective heat transfer is highly dependant on fluid velocity, so it is possible that the drop in convective heat transfer coefficient is more significant than the partial air recirculation, resulting in a lower thermal dissipation.

I'm not saying you're wrong because you have seen yourself that your temperatures dropped. I'm just saying there is a possibility that in some cases elaborate ducting schemes don't actually help.
 
Kaldskryke said:
I'm not saying you're wrong because you have seen yourself that your temperatures dropped. I'm just saying there is a possibility that in some cases elaborate ducting schemes don't actually help.
Click to expand...

This is no elaborate ducting scheme, and I am quite aware of fluid dynamics and resistance matters.....this is simply taping up a hole that vents back into the case, there is no extra ducting since I added nothing tot he length of the stock heatsink.
 
Could you show a pic and circle or otherwise mark exactly where you taped the vents? Trying to visualize it from a verbal description is giving me a headache.:)
 
80C for RTHDRIBL is pretty hot. My 612/900 GTS is around 70C running that. It could be your case is kinda hot inside, but taping up the vents will reduce airflow CFM, reducing cooling in the process as well. Now I'm sure that less heat from the card getting back into the case is helping some, but I cant help but wonder what your temps would look like with a slot blower instead.
 
Another option is to create a sort of ramp by taping a piece of plastic that goes from the card to an open slot below the card. In this way the hot air that is coming out of those vents still gets directed outside the case (through the open slot) and not recirculated in the case. It avoids the potentially temp-raising method of taping the vents closed.
 
rschissler said:
Yeah, I'd like to see a pic of these vents too.
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Taping these vents DOES NOT make for hotter temps....I think you guys are simply misunderstanding where I am taping off....here...you are making the air STAY in the heatsink a bit longer and forcing it to go OUT OF the case instead of exiting the vent and getting sucked right back into the heatsink fan....which makes the card itself run cooler and REDUCES case temps. 80c is NOTHING to these cards, they are not like a cpu, and at stock cooling parameters under extreme load, 80c in actually quite OK for an overclocked GTS. Keep in mind that the card in the case is upside down compared to the pic I attached...

8800gts_vents.JPG
 
I'm using the slot blower thingie just like Elmo, I found some drop in temps, but not by a lot.

I have the ACS3 version, maybe I'll try putting a fan on the back ... but I already have so many fans, my air-flow is kinda messed up in my case.
 
AndyM said:
Smaller outlet=more restriction=less airflow.
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It's very minimal restriction, and by leaving those vents open, it dumps part of the hot exhaust right BACK into the heatsink intake.


You can decrease restriction all you want by opening vents all over the top, but if you dump hot air back into the intake, you would get worse temps, period.

My case is "moderately" cooled, but VERY quiet, hence this may work well for me, while someone with alot higher cfm case might not see the gains I have.


It works for me, and that's all I care about :p
 
Blue Falcon said:
Elmo has the right idea though - I bet the sales of slot blowers have increased quite a bit thanks to the G80 boards. :p
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I'll never buy one of those things. I've found those things to be nothing but a marginally functional gimmick that eats up valuable space.
 
Dan_D said:
I'll never buy one of those things. I've found those things to be nothing but a marginally functional gimmick that eats up valuable space.
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Same here. I never found them to move enough air to even matter....
 
Quote:
Originally Posted by Dan_D
I'll never buy one of those things. I've found those things to be nothing but a marginally functional gimmick that eats up valuable space.


i concur,simply a waste of space and more noise
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Normally I"d agree about the slot blowers, but not in the case of the 8800 cards. I got right around a 10c drop in load temps from just adding a slot blower right under my GTX. It got into the low 80's before, now I load in the low 70's.
 
Do those slot blowers pull in air from the outside or do they exhaust to the outside, because I would think blowing air up into the vents that are supposed to be exhausting hot air would cause a resistance to the airflow. Basically you got hot air from the video card trying to move towards the rear of the case, some of it spills out those vents inside the case, and some of it goes out the rear (hopefully most of it). But if you blow air straight up into the vents, won't you be almost blocking any air from making it out the back?
 
[F8];1030684403 said:
Do those slot blowers pull in air from the outside or do they exhaust to the outside, because I would think blowing air up into the vents that are supposed to be exhausting hot air would cause a resistance to the airflow. Basically you got hot air from the video card trying to move towards the rear of the case, some of it spills out those vents inside the case, and some of it goes out the rear (hopefully most of it). But if you blow air straight up into the vents, won't you be almost blocking any air from making it out the back?
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There are two kinds - intake and exhaust. You'd want to use the exhaust kind for the reasons you explained.
 
If you really want to drop the temps then take off the cover to the 8800 and take out the fan and stick a 80-120mm fan onto it. That put my temps about 15C lower.
 
Looks like you need one of those Antec slot coolers. What does that do to your case temps?

BTW I modded a PCI slot cooler so it pulls the hot air our of those "slots". Those things really move a lot of air compared to a standard 80mm fan. They are quiet too. I used velcro to attach it to the top of the video card so if I ever need to rma it I can just pull the velcro off. It wont fall off either because it is on top of the video card (I have one of those inverted cases.
 
TridenT_Boy3555 said:
If you really want to drop the temps then take off the cover to the 8800 and take out the fan and stick a 80-120mm fan onto it. That put my temps about 15C lower.
Click to expand...

Have you though about trying to direct that fan so some of the air blows out of the case? I'm just wondering how much having that hot air in the case is affecting things - not much if you have good ventilation but my case ventilation is not the best so I'm hesitant to go with your approach (though I've used it on a lot of other cards).
 
Yea, the temps don't rise much. But see, I sold the card and mobo about a week or so ago. But yea you can arrange it so the air shoots out back.
 
I'm running a PCI exhaust fan on the second slot below my 8800GTX so there's a case slots worth of space between the video card and the PCI fan.
My GTX is currently ideling at 54c. Not sure what it's running under load, but I ran some of the stress tests in the NVidia tool and it only went up to 62c.
Not bad, and you know what... it didn't have to put tape and cardboard on my PC to do it :p
 
Phoenix426 said:
I'm running a PCI exhaust fan on the second slot below my 8800GTX so there's a case slots worth of space between the video card and the PCI fan.
My GTX is currently ideling at 54c. Not sure what it's running under load, but I ran some of the stress tests in the NVidia tool and it only went up to 62c.
Not bad, and you know what... it didn't have to put tape and cardboard on my PC to do it :p
Click to expand...
Just a $5 PCI slot fan.
 
Phoenix426 said:
I'm running a PCI exhaust fan on the second slot below my 8800GTX ...
Not bad, and you know what... it didn't have to put tape and cardboard on my PC to do it :p
Click to expand...


No cardboard here, and nobody can even see the clear scotch tape, and I gained ~5c better cooling under load. I could care less about idle temps actually....
 
Dan_D said:
I'll never buy one of those things. I've found those things to be nothing but a marginally functional gimmick that eats up valuable space.
Click to expand...

True except for the case of the 8800GTS/GTX cards, wherein the fan intake sits directly on top of the slots on the card cooler and basically sucks all of the hot air out of the cooler at a rapid rate. Marginally functional? Say that after you feel the hot air coming out of the PCI slot cooler's exhaust at high velocity, and after you've experienced GPU temperatures several degrees lower. :)


With that being said I wouldn't have even replied to this thread if I had paid attention to who the original poster was. :p
 
Blue Falcon said:
With that being said I wouldn't have even replied to this thread if I had paid attention to who the original poster was. :p
Click to expand...


You got a problem with me? Don't beat around the bush, let me know. You aren't the boss of the forums, and you talk as much crap as anyone. You seem to be a know it all at times...the fact is, my method works for ME, and if you don't like it you can shove it you know where....
 
Cooler Master Stacker case with 120mm exhaust fan sitting over the area where the vents are, for the win imo.
 
I cut up the bracket on the back of my slot cooler so I could affix it TIGHTLY up against the 8800GTS. I saw a temp drop between 5C and 10C.

Squirrel cage slot cooler = good.
 
Any fairly quiet slot blowers on the market? All the ones I have ever heard were basically either jet-engine loud or pretty loud to the point of not using it.
 
Using electrical tape on those vents DID increase my temperature a little bit...

I went from 72c load to 75c load, but it reduced my system temperature by 9c... It was worth it.

I then tried an undervolted blower fan (5v, still clicked a bit, but was fairly quiet) to remove the heat exhausted from those vents (obviously I untaped them).

Best of both worlds. load temps of 69, and system temps still down about 8c.


Rapture, if your temps decreased by taping those vents, You've definitely got a case airflow problem, as you may have mentionned (I didn't read the entire thread).
 
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