How does my case take air from the front when i don't have an intake fan?

[AleksiDj73]

This is a dumb question but i want to know how that happens. I have an old case from like 2007 and haven't changed it since. I cannot give you the exact google photo or take a photo of my case cuz i cba lol, well i cannot find the google photo cuz it doesn't seem like it exists. Anyways, to put that in context, picture a simple case from 2007-2008, black color without any intake fans with small little holes in the front, idk how to describe it better, anyways. I do not have any intake fans and the only fans that are currently working is the CPU fan, PSU and exhaust fan, GPU fans are off cuz there is no need to run at low temps. When i put my hand in the intake "fan" of my tower, i feel air getting sucked in and the RPM of it let's say it feels like it's 400-500 RPM but again, there is no fan, how's that possible? After a few weeks time, the intake builds up dust and every now and then it needs cleaning. There are literally only 3 fans working in the whole case and these fans are in the top left of the case and the intake is in the bottom right corner. I mean, the fans of these 3 parts are not running at a robust speed, when browsing, the CPU fan is 1500 RPM, the exhaust 1100 RPM, the PSU unknown and GPU off at low temps. When gaming, everything the same except the CPU ofc being at 2k RPM and the GPU fans running and stopping every like minute or so. Yea i know this a stupid question but i want to know the physics of it. Thank y'all.

[NLamki]

8 minutes ago, AleksiDj73 said:

This is a dumb question but i want to know how that happens. I have an old case from like 2007 and haven't changed it since. I cannot give you the exact google photo or take a photo of my case cuz i cba lol, well i cannot find the google photo cuz it doesn't seem like it exists. Anyways, to put that in context, picture a simple case from 2007-2008, black color without any intake fans with small little holes in the front, idk how to describe it better, anyways. I do not have any intake fans and the only fans that are currently working is the CPU fan, PSU and exhaust fan, GPU fans are off cuz there is no need to run at low temps. When i put my hand in the intake "fan" of my tower, i feel air getting sucked in and the RPM of it let's say it feels like it's 400-500 RPM but again, there is no fan, how's that possible? After a few weeks time, the intake builds up dust and every now and then it needs cleaning. There are literally only 3 fans working in the whole case and these fans are in the top left of the case and the intake is in the bottom right corner. I mean, the fans of these 3 parts are not running at a robust speed, when browsing, the CPU fan is 1500 RPM, the exhaust 1100 RPM, the PSU unknown and GPU off at low temps. When gaming, everything the same except the CPU ofc being at 2k RPM and the GPU fans running and stopping every like minute or so. Yea i know this a stupid question but i want to know the physics of it. Thank y'all.

At the exhaust fans are probably acting as intakes. What I mean is the back exhaust is pulling air from the front, if there is no air then naturally outside air will be pulled in, through those holes you mentioned earlier. 

[Grabhanem]

Basically the exhaust fan is reducing the air pressure in the case, so more air is getting sucked in via the easiest route, which happens to be the front vent.

[AleksiDj73]

7 minutes ago, NLamki said:

At the exhaust fans are probably acting as intakes. What I mean is the back exhaust is pulling air from the front, if there is no air then naturally outside air will be pulled in, through those holes you mentioned earlier. 

I thought that as well but you are right cuz i turned the the exhaust fan from 1100 to 600 RPM and i saw a small noticeable difference in the intake but how is that happening? I mean, the exhaust fan is in the other side of the case and the case is a mid tower size it's not like a SFF or something like that so how does the exhaust fan take air from the front when the exhaust fan is in the back? But at least it's sucking air which is good i guess

[AleksiDj73]

1 minute ago, Grabhanem said:

Basically the exhaust fan is reducing the air pressure in the case, so more air is getting sucked in via the easiest route, which happens to be the front vent.

Gotcha gotcha, it makes sense

[aDoomGuy]

If a case have more exhaust than intake you will have negative pressure. In your case you don't have any intake so your cooling is powered by the effect of negative pressure. When your exhaust draws air out of the case it creates low pressure and air gets sucked in naturally through cracks and openings in your case. The main downside to this is that dust can enter the case anywhere air enters the case but cooling can still be ok.

 

If you have more intakes (like me: 3x120mm+1x140mm intake fans and only 1x120mm exhaust) you will have positive pressure. If also like me you have dust filters then dust will have a hard time making its way into your case. In stead of getting sucked in through gaps in the case air gets forced out and dust can't get in that way.

[AleksiDj73]

20 minutes ago, aDoomGuy said:

If a case have more exhaust than intake you will have negative pressure. In your case you don't have any intake so your cooling is powered by the effect of negative pressure. When your exhaust draws air out of the case it creates low pressure and air gets sucked in naturally through cracks and openings in your case. The main downside to this is that dust can enter the case anywhere air enters the case but cooling can still be ok.

 

If you have more intakes (like me: 3x120mm+1x140mm intake fans and only 1x120mm exhaust) you will have positive pressure. If also like me you have dust filters then dust will have a hard time making its way into your case. In stead of getting sucked in through gaps in the case air gets forced out and dust can't get in that way.

I get you lad, thanks for the detailed explanation. I clean out my case (and components ofc) every month or so so it's not like i leave it build up dust or anything, i literally cleaned out my case 40 mins ago so yea. Cooling is not terrible, it's mediocre. Here's the thing, if my exhaust fan runs at 550 RPM, the GPU temp will be 57c lol, when i turn up the exhaust fan to 1100 RPM, the GPU temp goes to 45c in like 10 mins so that's why i have my exhaust at 1100 RPM at all times.

 

Fun fact, i watched LTT's video today about the 3 PCs benchmark for the airflow specifically and it was quite interesting to say the least and it makes sense

[aDoomGuy]

8 minutes ago, AleksiDj73 said:

I get you lad, thanks for the detailed explanation. I clean out my case (and components ofc) every month or so so it's not like i leave it build up dust or anything, i literally cleaned out my case 40 mins ago so yea. Cooling is not terrible, it's mediocre. Here's the thing, if my exhaust fan runs at 550 RPM, the GPU temp will be 57c lol, when i turn up the exhaust fan to 1100 RPM, the GPU temp goes to 45c in like 10 mins so that's why i have my exhaust at 1100 RPM at all times.

 

Fun fact, i watched LTT's video today about the 3 PCs benchmark for the airflow specifically and it was quite interesting to say the least and it makes sense

Yeah bro. If you want more silent operation just add a front fan if possible. It will also make that rear fan of yours last a bit longer, temp wise you should be perfectly fine as you've seen. My previous PC I ran with 2x120mm intakes and 120+140mm exhaust so that was negative pressure too and I could always count on gaps in the case for extra cooling if overclock was high hehe. The only issue though was dust everywhere. 

 

When I ordered the components for this build I wanted to try positive pressure because dust is a killer and I find it a pain to get rid of. My PC is not dust free inside, the tiniest dust particles (they look like powder) still manages to find it's way through the filters but they mostly stick to the glass panel, the backplate on the video card and on the bottom of the case. I had my CPU cooler off not long ago and there wasn't much there so just a careful wipe on the video card, top of the PSU cover and the glass panel seems to be enough for maintenence. Apart from blowing off dust filters.

[AleksiDj73]

10 minutes ago, aDoomGuy said:

Yeah bro. If you want more silent operation just add a front fan if possible. It will also make that rear fan of yours last a bit longer, temp wise you should be perfectly fine as you've seen. My previous PC I ran with 2x120mm intakes and 120+140mm exhaust so that was negative pressure too and I could always count on gaps in the case for extra cooling if overclock was high hehe. The only issue though was dust everywhere. 

 

When I ordered the components for this build I wanted to try positive pressure because dust is a killer and I find it a pain to get rid of. My PC is not dust free inside, the tiniest dust particles (they look like powder) still manages to find it's way through the filters but they mostly stick to the glass panel, the backplate on the video card and on the bottom of the case. I had my CPU cooler off not long ago and there wasn't much there so just a careful wipe on the video card, top of the PSU cover and the glass panel seems to be enough for maintenence. Apart from blowing off dust filters.

That's a good idea you know, idk why i haven't thought it but honestly, i'm just better of buying a new case cuz the current case i have is like 12-13 years old lol. I could buy like a 80mm fan and zip tie it to the front of the case idk, i'll see what i can do.

Nah, temps wise with the Intel stock cooler, the CPU in general is NOT fine lol, it is a joke, playing CSGO 1080p low settings, above 90c lol, wtf is that. I will buy however a new CPU cooler in a few days hopefully so i'll be good on that part.

 

Dust is impossible to keep out from a case, even if you have the most beast cooling you have on your case, you will see some dust after a while but the good thing is is that you can decrease the amount of dust. Also, no one's PC is dust free tbh so yea