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  Stock case airflow question 
 Date Written 
Mauricio Avalos Sep 20, 2010, 02:13am EDT Report Abuse
Hi guys,

I have an HP computer. I recently upgraded my GPU and I'm getting really high temperatures inside my case. Around 55 degrees celcius for both CPU and GPU at idle times and up to 80 degrees from my GPU when playing games. I have an ATI 5870.

The case that I have doesn't give me a lot of options to modify it to improve the temperatures. I don't know what you guys would suggest.

It has only two fans. One at the back, almost at the top, just below the PSU, blowing air outwards and one at the top of the case blowing air outwards also.

Both fans are running at a pretty low speed, I can barely feel any air coming out.

The PSU has a huge fan also, blowing air towards the Motherboard. I'm guessing it's taking air from the outside and blowing it in to the case.

I was planning on changing the stock fans to improve temperatures. I've never done this so I'd like to see if you guys know of a good brand of fans that will help me improve my temperature problem and also if it's correct that both fans are blowing air inwards. I was thinking of having the back fan blow air inwards and the fan at the top blow air outwards.

There is also no way of changing the speed of any of those two fans since they are both connected directly to the PSU.

Thank you so much for your time!

Edit: The back fan is connected to the Motherboard and the top fan is connected directly to the PSU.

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micro Sep 20, 2010, 11:07am EDT Report Abuse
>> Re: Stock case airflow question
As far as the brand of a fan. They all work well, it is just that a higher quality fan may be quieter and will last a lot longer. Just get what seems to be a name brand.I have Antec fans with a built on fan speed controller. THese cost about $10 each at my local staples store. I assume i can get them online for less though. You can also get a fan speed controller that sits in a dvd rom bay.

A case should have about as much air flow in as out. If not it tries to create a vacuum. This gives dead pockets of air, or low air flow. Thus they don't move very much air.

Your psu should be blowing air out of the case as well as your video card, not into the case. It may seem like it is blowing air in, but take the side panel off of the pc and hold a strip of paper over the fan to test its true direction of air flow.

You should have at least one fan blowing air in and the one near your mobo blowing air out the back, thus pulling air over your components/mobo, cooling them. Often times adding a snorkel from the case side, directly to the cpu will greatly increase its cooling (with or even without a fan on it). You can use a cardboard tube, or even plastic drain pipe for a sink.

You can also leave the side off of the case for better cooling on a standard case like this one.

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john albrich Sep 20, 2010, 12:08pm EDT Report Abuse
>> Re: Stock case airflow question

For budget setups, I've had good experiences with "Ultra" dual-ball-bearing 120mm fans. When on sale these can be a bargain. Quiet, long-life spans, decent air-flow. You can get them either as a 12vdc with a 3-speed integral controller switch if you don't have a speed control connector on your motherboard or a fan controller, or you can get them with a connector designed for the the speed controller of the motherboard or extra fan controller. Of course you have to buy the correct size fans, too.

You may wish to examine your case more closely. It's possible it has a front fan mounting point. This location is usually used to bring air into the case, help it flow over any hard drives, and then exit via an exhaust fan or other vent(s). These are often designed for 80mm fans. Their noise however can be more noticeable because they're at the front of the PC and they are smaller diameter fans...which usually have to run at higher speeds to move a decent amount of air.

Generally speaking, fan quality is a function of the bearing design. Brand does make a difference too.

For a given manufacturer and fan blade and housing design...

Sleeve bearings, the most common, are cheap, noisy, and wear-out quickly.

A ball-bearing fan is better

A dual-ball-bearing fan is even better

A ceramic bearing fan is even better

Noise is also a function of blade and housing design so even a very high-quality bearing fan can be noisier than a low-quality bearing fan.

A cheaply made fan may last less than 6 months.

john albrich Sep 20, 2010, 12:21pm EDT Report Abuse
>> Re: Stock case airflow question

Addressing Fan Speed

Mauricio Avalos said:
...Both fans are running at a pretty low speed, I can barely feel any air coming out.....

There are a few things that could contribute to a slow speed fan:

1) it just naturally maxes-out at a low speed

2) it may have an "in-line" 3-speed controller switch in the fan cable to the motherboard or a power connector. The controller switch may be set at the lowest position. Move the switch to another position and see if it makes a difference. This can be done while the power is on.

3) if it is connected to the motherboard, the default fan speed settings may be too low. These may be in BIOS and you MAY be able to adjust them. Some computers don't let you change the settings.

4) if it is connected to the motherboard and you can't change the settings, there are a number of things you can try:

4a) try getting a fan-power adapter that connects the fan directly to a +12V power connector (usually a 4-pin disk-drive connector). The downside of this is the fan runs at maximum speed ALL the time.

4b) try getting a 3-speed fan (like in item2), or a different fan, or control the fan using a separate hardware fan speed controller.

4c) try some fan speed control software. Using this software MAY allow you to increase the fan speed for a given temperature. For example, if your fan is currently running at 800RPM when the temperature hits 40degC, you may be able to change this so it runs at 1200RPM when the temp hits 35degC, thus keeping your system cooler. There are a number of freeware programs available that may work. Speedfan is one, Everest Home edition is another. Some programs work only with certain types of motherboards. Check compatibility when you search for the programs. Check download sites like,, softpedia,com, etc.

5) Keep your fans clean. A dirty fan will not only move less air (and thus your system will run hotter), but the fan may fail earlier as well.

Whenever you connect a fan to the motherboard/controller, make SURE that the motherboard/controller can handle the power requirements of the fan. Some motherboards can handle only fairly low-power fans (e.g. a few hundred milli-amps (~ 2 or 3 watts)). Plugging in a high-power fan can permanently damage your motherboard.

Mauricio Avalos Sep 20, 2010, 12:59pm EDT Report Abuse
>> Re: Stock case airflow question
Thank you so much for your suggestions.

Sadly I don't have much room to work with, I have checked everywhere and there are only two places where fans can go.
I'll try your suggestions.

Thanks again!

Dr. Peaceful Sep 20, 2010, 06:22pm EDT Report Abuse
>> Re: Stock case airflow question
Both Micro and John have very good suggestions for case fans in general. From your information, since you are able to add a regular GPU, I guess you have a mid-tower ATX desktop. However, since this is a pre-build brand name computer, it can potentially has proprietary components and/or non-standard layout. So in order for us to provide you more specific instructions, you should provide us the model name/number of your HP desktop and how long ago did you get it.

It is Crucial to know those information, in order to for us to look up the layout of the desktop case; what size and how many fans allowed; what kind of mobo (so we know how many fan power leads provided and whether it has fan speed control in the BIOS); what kind of PSU; what kind of CPU heat sink; how many PCI slots; etc. From those, we can help you find the best approach in optimizing your air flow and cooling.

Mauricio Avalos Sep 20, 2010, 11:35pm EDT Report Abuse
>> Re: Stock case airflow question
Sorry I took so long, but just got home hehe.

This is what my setup looks like:

I checked and yes the PSU is blowing outwards, I felt a breeze from it so I thought it was blowing inwards but I checked with a piece of paper and it is indeed blowing outwards.

So as you can see I have three fans blowing outwards. The PSU cabling is the best I could do, no room to put it anywhere else. It's blocking a bit of the top fan but not much.

Based on this what do you guys think the setup of my fans should be? The fan at the back plugs into the mother board so I'm not sure if I should buy one that connects to the PSU and get more power out of it without risking the motherboard.
Same goes for the top fan.
The question also is which fan should blow outward and which one indwards.

Thank you guys!

Edit: My pc is an HP Pavilion Elite d5000t ATX

Dr. Peaceful Sep 21, 2010, 12:12am EDT Report Abuse
>> Re: Stock case airflow question
A picture worth a thousand words, thanks for that, it will certainly help us help you better. Just as I predict, it's a pretty standard ATX case. I don't know what HP is thinking, why in the world that there's no front intake!

Both the top and back fan positions are suppose to be exhaust fans, so you can NOT reverse neither to be an intake. It will make matters worse.

Few things I would suggest:
1. A better CPU heat sink. One you have is very standard (stock) looking, which is not so good as some of the after market ones. The IPIBL-TX board is an Intel LGA 775 board, so you need a LGA 775 heat sink.

2. A cyclone type fan that fits in the PCI slot below the GPU card. It sucks air from the bottom of card and exhaust it out the back. Something like this:

3. What's on the side panel? Is there a vent opening? Probably you will need some modding here. I would mod it to put an intake fan here.

4. Like suggested above, better / faster / speed controlled fans would also help. The top one looks like a 8cm fan. The back one looks like 12cm. Looks like you still have some spare 4-pin molex left on the PSU, use those for the fans.

5. Since this is a very standard desktop computer. You might also think about changing case. Get a new case with more fan locations and better air flow to provide better cooling. It can be a good alternative solution.

Here are some good links for specs and general hardware handling of your PC, if you do not know already.

Mauricio Avalos Sep 21, 2010, 12:47am EDT Report Abuse
>> Re: Stock case airflow question
Dr Peaceful, and everyone else, you have been of great help. I didn't know those type of fans existed!
I will be taking your advice by upgrading the fans and having them blow outwards like you suggested.
Changing the case is not much of an option at the moment, I wanted a cheap solution to improve my temperatures but I'm just doing it to stay away from the danger zone, not looking for record low temperatures hehe.

Again than you everyone, you've been of much help!

Dr. Peaceful Sep 21, 2010, 12:56am EDT Report Abuse
>> Re: Stock case airflow question
You are welcome!

john albrich Sep 21, 2010, 05:07am EDT Report Abuse
>> Re: Stock case airflow question
Dr. Peaceful...I think with two top-oriented fans it might be beneficial to try using the lower rear-mounted fan to force cooler air IN to the case even though it isn't from the side or front. This would basically replace adding the "cyclone" fan in a card-bay. Generally speaking, I've found those cheap card-bay fans do little to nothing to help with internal temperatures, and the sleeve-bearings many of those fans use fail very early on.

It wouldn't hurt to try it and measure system, CPU, GPU, and hard drive fan temperatures for awhile.

During this experiment, even if it didn't prove helpful, nothing would even approach critical temp levels before he could manually intervene. He would have minutes...not seconds to respond.

However, since he has confirmed the rear-mounted fan is connected-to/controlled-by the motherboard, and assuming he can't change its speed via software, then he could definitely also look at connecting it directly to +12V and seeing if that helps. It's possible it is already getting +12V from the motherboard, but since he said it the air output from this fan was low it's still worth a shot.

Dr. Peaceful Sep 21, 2010, 01:32pm EDT Report Abuse
>> Re: Stock case airflow question
John, those are my suggestions, he can always experiment whatever he likes. By reversing the rear fan to intake air, there is a possibility that it will create a hot air loop: hot air from CPU rise to bottom of PSU -> PSU fan exhaust it to back -> suck back in by the rear fan below into case -> repeats cycle. If that happens, it's not very effective for cooling.

From what I observed from pictures of his case online, there are 3 different side panel styles: no vent, just a solid panel; small vent near the CPU; large vent at front bottom of panel. If what he has is the 3rd one, like shown in the link here: , then he can easily mod the panel to mount an intake fan at the vent. Probably just 4 drill holes will do. You can see from the same link, there are lots of perforations on the front of the case behind the front cover (though no place to mount a fan there). So air flow is not too bad (though not ideal), as long as his exhaust fans are able to generate enough negative pressure, air will go into the case passively. But an additional intake fan that takes in air actively will help even more.

Here's a rough air flow diagram I made using his case pic.

john albrich Sep 21, 2010, 03:18pm EDT Report Abuse
>> Re: Stock case airflow question
Dr. Peaceful said:
...By reversing the rear fan to intake air, there is a possibility that it will create a hot air loop: hot air from CPU rise to bottom of PSU -> PSU fan exhaust it to back -> suck back in by the rear fan below into case -> repeats cycle. If that happens, it's not very effective for cooling....

I considered that possibility, but unless the computer is located in a fairly enclosed space, the vast majority of the warmer air expelled from the PSU vent quickly rises and will not be cycled back into the case by the lower rear-mounted case fan to any significant degree.

This also is a very easy and safe test to conduct, it would not take much time, and based on his picture, the cooling benefits (esp for the CPU) could be significant for $0.

I agree that experimentation and monitoring the temperatures is what will yield the answers.

Mauricio Avalos Sep 21, 2010, 06:10pm EDT Report Abuse
>> Re: Stock case airflow question
I reversed the rear fan and my GPU temperatures increased by 10 degrees celsius lol.

I gave yet to try reversing the top fan. I will try that tonight. But I will get more powerful fans in any case.

john albrich Sep 22, 2010, 11:02am EDT Report Abuse
>> Re: Stock case airflow question


But one thing this strongly suggests, is that the first (and relatively cheap) thing you might try is installing a higher CFM fan in that position. This would probably reduce the GPU temp by a pretty fair amount (of course, put it in the default position so that the fan exhausts air from the case). But before doing that you still might get more CFMs out of the existing fan by attaching directly to 12V...but as indicated earlier it depends on whether it already is connected directly to 12V or its RPMs can be increased by some method.

This result also suggests your GPU heatsink is properly attached and working fine. Otherwise it wouldn't have made such a quick and significant difference. So, that's good info.

Mauricio Avalos Sep 24, 2010, 12:57am EDT Report Abuse
>> Re: Stock case airflow question
Got an Excalibur fan to replace the back fan.
No difference at all :(!
Maybe 1-2 degrees but nothing more.
I also have the PCI fan below the GPU and that took away maybe 2 degrees also.

Guess there's nothing more I can do with this case :/

john albrich Sep 24, 2010, 06:09am EDT Report Abuse
>> Re: Stock case airflow question
Mauricio Avalos said:
Got an Excalibur fan to replace the back fan.
No difference at all :(! Maybe 1-2 degrees but nothing more.
I also have the PCI fan below the GPU and that took away maybe 2 degrees also.
Guess there's nothing more I can do with this case :/

If the Excalibur is also plugged into the motherboard (as was the original fan per your post of ), it too may not be operating at maximum CFM/RPM and would help explain why it might still not make a significant difference.

Have you tried plugging the Excalibur directly to +12V?

However, perhaps your case is also relatively tightly least around the panel edges and up front...which limits letting in cool air...and maybe the only resolution is to add more openings. Didn't someone suggest adding more vents a bit earlier in the thread? There are a few threads on HWA (and other sites) on the easiest ways to create decent looking venting in the side panel. I've fairly easily modified a few case side panels using a hand-tool called a "Nibbler".

Or, if the side panel removal design is like most computers, perhaps as another free approach you could just slip it back a bit (maybe 1/4" or so) toward the rear so there's a small opening in the side, from top to bottom near the front of the case. Just enough so the rear panel stays on. The cumulative effect would be adding a few sq. inches of venting and give those exhaust fans to pull more air across the components from front to back. As a stop-gap measure it wouldn't look too bad, and of course is completely reversible and free just in case doesn't do anything to help.

But then, I've always tried to keep costs down while experimenting. Sometimes it's just best to "bite the bullet" and buy a better case designed for adequate cooling and move everything over into it. You can occasionally find a very decent case on sale/rebated for $25 or so, and as long as you check the measurements, and ensure it's compatible with your motherboard, PSU, etc. it's easy to do.

edit to add:
By the way, you might consider editing your first post so that it reflects that your fans were connected to the motherboard and not connected directly to the PSU

G. G. Sep 24, 2010, 09:25am EDT Report Abuse
>> Re: Stock case airflow question
is your pc still under warranty? Seeing that your psu is an aftermarket, im thinking that you are outside your warranty period.


Mauricio Avalos Sep 24, 2010, 10:14am EDT Report Abuse
>> Re: Stock case airflow question
Thanks guys,

yes as you have mentioned probably the only option left is to make a side vent by myself.

The Excalibur fan is connected to the PSU, running at max speed. It's VERY noisy but there is no 4 pin connector on my motherboard other than the one for the CPU.

The excalibur actually runs at a lower speed compared to my last fan if I connect to the mother board.

This pc can't be upgraded any further and yes I've lost warranty.
That's why I'm hesitant to buy a new case (although I know that will help me if I decide to build a new pc in the feature).

Thank you for all the help guys, I think for now I will leave it here and in a few months I'll start thinking on building a new pc.

You've all been very helpful!

G. G. Sep 24, 2010, 10:37am EDT Report Abuse
>> Re: Stock case airflow question
The reason I asked about the status of warranty is my suggestion would be to replace the case with one that has more airflow capabilities.

The other reason that your temps went up is due to your upgrade of your gpu. First off, the HP case was originally "designed" for the original setup. Remember...... prebuilt computers from the likes of big brand box manufacture that the design are only meant for the original setup... not future upgrades. Onther thing... your upgraded gpu... from the looks of it. you got a 5870 that has the fan in the middle of the card. With this design, you have better heat disappation but the downside is that half the heat exits the case and the other half of the heat gets dumped into the case. In a case that has good airflow, heat issue is not a problem. But in your HP case that has no intake fan, the current setup has issue evacuating the heat from the internals. Now if you had gotten a 5870 with the squirl cage fan on the end of the card where most of the heat exits the rear of the case, the additional heat disappated into the case may or may not be an issue... but this design is less efficient for the gpu.

So, I think you are still viable to upgrade your case to one that is more conducive to better cooling for the current pc and the upgraded case can be used for future build.

Here are just a couple of recommendations:

Cooler Master HAF 932 - (140mm rear and 230mm for top, side, & front)

Cooler Master Sniper - (120mm rear and 200mm for top, side, & front)

Both case are extremely strong (no flexing) and EXCELLENT airflow.

So by doing a new case now, you will help your situation today and be ready for your future upgrades.

oh by the way, excellent pricing for the Sniper case.





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