Exhaust temps - possible to keep cooler?

G

grit

Limp Gawd
Joined
Jul 29, 2002
Messages
136
I'm trying to find a way to keep case exhaust temps cooler so i don't heat my room up, but without making my case noisy. As an example, I gave up on a GTX 480 with stock heat sink because for me, that is way too noisy while playing games.

Skip to the bottom paragraph if you want to avoid reading about MY specific case & components currently.


I currently have a Lian Li PC-7F type case with Noctua fans. I did remove the internal HDD cage to hopefully get better airflow from the front. If you're not familiar, its a 140mm intake in the bottom front and a 120mm exhaust in the back by the cpu. The PSU is on the bottom and supposedly intakes from the bottom through slots, exhausting out the back. Components are an Intel 930 w/a Venomous X & Noctua fan. GPU is back down to an ATI 5870, but with the newer fan & heatsink that does not exhaust air. The case fans are at full power. There's also 1 optical drive and one SSD. No conventional HDDs in the case.

A few days ago, I was playing with a Zotac GTX 480 amp, which is quieter than stock, but also does not exhaust heat. In a very open area, I found the back part of the top of the case to be VERY hot to the touch. Probably about 125 degrees F. The back exhaust was equally hot. CPU was up at near 50 degrees C and GPU was at 70 C (per Everest Ultimate) while gaming. The hot air from my case definitely warmed the area. In contrast, my friend's AMD / 8800 GT system in an Antec 900 case had cool exhaust.


So, all of that to ask - is it possible to have enough cooling in a case (non-water cooled) that exhaust temps will not alter the overall room temperature of a small (12'x12') room? Because right now, the exhaust is HOT and the room temp goes up by an easy 10 degrees F while gaming.
 
Seriously though you can't do a direct comparison to your friends much lower power consuming better vented setup. Only way to improve airflow without noise is to cut some more holes or remove some filters. Maybe invest in some higher CFM Scythe fans or even an aftermarket cooler for the GPU.
 
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I was a bit worried that what you stated might be the case. I have NO idea what the thermals for a new AMD system are, and I'm really not with the 8800 GT either.

I also should have more clearly stated what I'm considering or willing to consider:

- top intake fans in my current case. my concern is that doing so will create noise and more dust in the system (from lack of filtered intakes)

- a Corsair H50 or Coolit Eco, but I'm not sure if that will help whatsoever? Thermals should be similar to a Venomous X, no?

- a completely new case, such as that Antec 900. The only mod I want to have to do is fan replacement and adding handles (I take it to LANs, and I can't afford to build a second LAN-only system).
 
A 8800 GT takes less than half the power of a 480 GTX at load, so really there is no comparison. I don't think a budget water cooling would make that much of a difference compared to a good air cooling solution. Your best bet would be to modify your case (with a top blow hole) or get a new one with better airflow. Right now it seems it's intaking past the GPU and exhausting where the CPU is. As an ersatz solution you can remove your drive bay covers and stick a big silent fan there as the direct air path would cool things down quite a bit I bet.
 
Or you can just go for that Antec 900, which pretty much does all that for you, but might be a little bit noiser since there are so many holes. An aftermarket GPU cooler still might be a good investment if you plan on sticking with your GPU.
 
Your computer is making the same amount of heat and regardless of how it is dissipated, it's all ending up in the same place - the air in your room. Doesn't matter how many fans, holes, etc you have - if you ran a completely sealed case that radiated heat or a completely open case it's the same.

The ONLY way to lower the heat dump into your room is to either find a way to get the heat out of the room (eg watercool your pc and place the radiator outside somewhere) or to use lower powered components.
 
Well right again laws of physics, but OP could improve efficiency and thereby lower power consumption with better cooling - albeit slightly.
 
Superglue a Dryer exhaust tube to the back, cut a hole in the wall, and nail the tube to the opening. Then all of your heat will go outside and your room will stay nice and cool.
 
Lol! I like that idea. I was hoping to just keep the exhaust cooler. I figure the A/C can manage it easier if it isn't so hot in the case. I think I ay try the top exhaust and see how that works. has anyone tried blocking their top exhaust to see how adverse the effects are?
 
Just like the clothes dryer in your home. A funnel exhausts the hot air from the dryer outside through the wall.
This would be the most extreme mod a PC owner could ever do.
 
Notleh said:
Superglue a Dryer exhaust tube to the back, cut a hole in the wall, and nail the tube to the opening. Then all of your heat will go outside and your room will stay nice and cool.
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That would honestly be the solution I'd recommend, minus the cutting the hole in the wall. Build a bracket for a window and put it out there. Be sure to put a decent filter on the outside so crap can't climb in there and make a nest and ruin your cooling or put bird shit in your PC.
 
OK, I admit I was taking the piss on the cutting the hole in the wall thing.

However...the more I think about it...the more I think there may be some merit to this idea. My 470GTX in SLI put out ALOT of heat with those fans running full power. I think I may get a little crazy and try something. :D
 
So I got to thinking about this... I went to home depot and found a portable air conditioner. The exhaust system is designed to be placed in a window, kinda like those fans that are built to go into windows. Point is, it has a hose with a window mounted exhaust. All I need to do now is find the hose and mount separately and connect them to my computers exhaust.

Seems like lots of work just to keep the room cool. I returned the GTX 480 and put the radeon 5870 back in to help. I wish water cooling or some other solution would allow me just to keep the exhaust temps down
 
I put my PC to sleep when I am not using it. Helps keep the space cooler and it saves on electricity. Also, I don't get know where near the dust in my case.
 
vsboxerboy said:
Your computer is making the same amount of heat and regardless of how it is dissipated, it's all ending up in the same place - the air in your room. Doesn't matter how many fans, holes, etc you have - if you ran a completely sealed case that radiated heat or a completely open case it's the same.

The ONLY way to lower the heat dump into your room is to either find a way to get the heat out of the room (eg watercool your pc and place the radiator outside somewhere) or to use lower powered components.
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please understand this part...
 
Undervolt everything. You can get drops of more than 10c on both the GPU and CPU. And it's free.

Theres guides here

Hot things will make the same amount of heat whatever the cooling is. Unless you go full peltier/phase change, which is expensive/possibly dangerous. Water cooling just transports heat. The radiators are going to still dump the same heat back into the room.
 
I do get the idea - that the system components will give off a particular amount of heat, depending on how how much they are working of course (eg, more playing a game than in idle). I understand that nothing (short of under-volting) will change the amount of heat energy that they give off.

What I'm trying to figure out is the ability of my room to dissipate that heat, and whether or not excessive air flow in the case will help. My room isn't a closed system. It's a bedroom that I use as an office, with window, ceiling fan, door, and air conditioner (whole house, not single room a/c).

We've seen enough reviews to know that the faster the fan, the lower you can get the heat sink, but it costs you noise. What I'm wondering is that, if I use that "faster fan", will that start dissipating the heat energy from the computer sooner (ie, at a lower temperature), thus allowing my room to handle the heat before it builds up in my room.

I'm sorry I haven't worded this better, or sooner. And if my theory is still just wishful thinking, then it is. I just want to make sure I'm asking the question correctly. I can completely understand the responses I've gotten, assuming the room was a closed environment. And for all I know, all the windows and fans don't make any difference. That's why I asked here - there's always someone smarter and with more experience than me. :)
 
grit said:
What I'm trying to figure out is the ability of my room to dissipate that heat, and whether or not excessive air flow in the case will help. My room isn't a closed system. It's a bedroom that I use as an office, with window, ceiling fan, door, and air conditioner (whole house, not single room a/c).

We've seen enough reviews to know that the faster the fan, the lower you can get the heat sink, but it costs you noise. What I'm wondering is that, if I use that "faster fan", will that start dissipating the heat energy from the computer sooner (ie, at a lower temperature), thus allowing my room to handle the heat before it builds up in my room.
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I get what you're trying to say, I think. Basically the surrounding environment will heat up the same regardless of your cooling setup. If you push more air through a case then the exhaust air is going to be cooler, but you'll be heating a greater volume of air. The amount of heat energy moved from the computer to your environment is the same.

The only way to sidestep the issue is to ensure that the heat is moved out of your immediate environment. Just think of your room as a giant computer case, and your computer as the CPU heatsink. Its the same concept on a larger scale.

No amount of tinkering with stuff inside your computer room will make it any cooler. The only way to cool your room is to start moving the air out of it. You can either exhaust hot air from your computer outside or into another room, or you can increase the amount of cold air coming into the environment, which will also displace the hot air as it finds its way back into your A/C unit's intake.
 
grit said:
What I'm trying to figure out is the ability of my room to dissipate that heat, and whether or not excessive air flow in the case will help. My room isn't a closed system. It's a bedroom that I use as an office, with window, ceiling fan, door, and air conditioner (whole house, not single room a/c).
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Well, if you get enough delta fans and point them toward the door, then yeah, I guess you CAN make enough airflow to blast the hot air right out of your room lol.

BUT I do think I understand what you're asking - is there a positive feedback loop where hotter case temperatures lead to hotter components which lead to hotter case temperatures, ..., ... amounting to more heat in the room at the end of the day. THAT is a question that I'm not sure about. I know that at the extremely high temperature ranges that leakage can occur, lowering the efficiency of the processors so that would make sense. However, how much and at what temperature level - I'd probably say that you're currently well within the range of 'you won't notice a difference'
 
get some high speed fans that blow all that hot air out the window. either that or turn up the ac in your room when you game. oh yeah and the ceiling fan too! that heat has to go somewhere.
 
NKDietrich said:
I get what you're trying to say, I think. Basically the surrounding environment will heat up the same regardless of your cooling setup. If you push more air through a case then the exhaust air is going to be cooler, but you'll be heating a greater volume of air. The amount of heat energy moved from the computer to your environment is the same.
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Ok, that makes sense to me. Just a sharing the heat to a larger volume of air. The exhaust feels cooler, but the overall heat is the same.

Now that I understand it all, what's the point of cases with crazy fans and big air flow then? As long as you have enough airflow to keep your components within tolerance levels, why bother with more fans? The only reason I can see is noise level. However, my case is pretty quiet with just a 140mm in front and 120m in back. Nothing's overheating or even close to it. What's the advantage of cases with three 200mm fans?
 
Having more or larger fans can do two things; 1 - it allows you to setup an airflow through your case with slower and thus quieter fan speeds for the same volume of air movement and 2 - it allows you to eliminate deadzones where air was not previously circulating. Keep in mind though that more fans absolutely does not mean more efficient flow. Balancing intake and exhaust volume per minute is important but a lot of times these cases with way too many fans are only for marketing or aesthetic value.
 
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grit said:
Ok, that makes sense to me. Just a sharing the heat to a larger volume of air. The exhaust feels cooler, but the overall heat is the same.

Now that I understand it all, what's the point of cases with crazy fans and big air flow then? As long as you have enough airflow to keep your components within tolerance levels, why bother with more fans? The only reason I can see is noise level. However, my case is pretty quiet with just a 140mm in front and 120m in back. Nothing's overheating or even close to it. What's the advantage of cases with three 200mm fans?
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Well the definition of "overheating" is different for people. Some folks are overclocking and need the extra cooling to maintain reasonable temperatures and stability. Others are just more comfortable keeping temperatures low, others are running a ton of crap like two or three video cards and their system just needs the air.
 
The High flow cases are doing exactly what it says they are.. moving alot of air in and out of the case. The whole point isn't to produce less heat, but to get it out of the case. All of the different heatsinks (CPU, GPU, VRM/ MOSFET, RAM) work as a coefficient of the surrounding air.. the hotter the air, the higher the temperature of the component. There isn't any more or less heat being produced by the electronics, they simply aren't being cooled as well ( a CPU producing 120 watts of heat is the same wattage whether it's running at 95f or 125f )
If the air going INTO the PC is substantially cooler, the thermal rise, everything else being equal , would be the same, leading to lower exhaust temps. But this would pretty much mean ducting Air Conditioning directly into the PC. If you only have one vent, the end result would still be the same tho, as the cool air mass is now gettin dumped into the room at a higher temp.
 
I would run a duct to a window and build a shroud to close the window around the ducting. You could even go as far as putting an AC powered 120mm fan against the shroud to pull air through the duct. Your shroud to mount the ducting could even be some clear plastic so you can still get light through that portion of the window opening. A trip to Home Depot and maybe $20 for materials would finish this project. An AC powered fan on the other hand... well that's up to you on that one.
 
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