Best Air Flow Config?

[andersdog]

I have a Corsair 500R, with this in it at the moment:

 

mobo: Gigabyte z87-d3hp

cpu: 4670k + stock cooler

gpu: Asus r9-280x-dc2t

3xhdds in the bottom cage

 

There's other stuff, but I doubt it'd obstruct or require much airflow.

I'm going to replace the stock cooler with a D-15, and I plan to replace the 500R's stock 12cm fans with 3 x S12A PWMs (2 x front in, 1 x back out), while leaving the side panel's 200mm fan as an intake, for now. 

The specs I've found for the side fan suggest it's max airflow is 92cfm (156m3/h), which doesn't sound right. I'm concerned that the two front intakes won't be enough for the 280X and the D-15. The PSU I *might* be able to turn upside down and fit another intake down the bottom. 

Failing that, should I stick an intake at the top near the front to help feed the D-15 and prevent starving the GPU of airflow? Or, will it likely be ok as is and I should just try it out and see? Or... what else would you recommend?

Any thoughts much appreciated.

[LogicalDrm]

-

 

You will have plenty of intakes. D15 will take part of its air from GPU exhausting anyway and upper front intake should provide air mainly to it.

[spwath]

I have a Corsair 500R, with this in it at the moment:

 

mobo: Gigabyte z87-d3hp

cpu: 4670k + stock cooler

gpu: Asus r9-280x-dc2t

3xhdds in the bottom cage

 

There's other stuff, but I doubt it'd obstruct or require much airflow.

I'm going to replace the stock cooler with a D-15, and I plan to replace the 500R's stock 12cm fans with 3 x S12A PWMs (2 x front in, 1 x back out), while leaving the side panel's 200mm fan as an intake, for now. 

The specs I've found for the side fan suggest it's max airflow is 92cfm (156m3/h), which doesn't sound right. I'm concerned that the two front intakes won't be enough for the 280X and the D-15. The PSU I *might* be able to turn upside down and fit another intake down the bottom. 

Failing that, should I stick an intake at the top near the front to help feed the D-15 and prevent starving the GPU of airflow? Or, will it likely be ok as is and I should just try it out and see? Or... what else would you recommend?

Any thoughts much appreciated.

Its fine, it will be fine.

There is plenty of airflow

[andersdog]

Thanks LoGiCalDrm and spwath

[patrickjp93]

The point of positive air pressure it to make dust gravitate to the edges and corners of the case instead of to the components. There is a sweet spot to maintain flow through the case while still letting dust fall to the floor, and it's different with every case. For my Lian Li it's 12 CFM extra going in than out supported by a Noctua Nf F12 for intake and a cheap aerocool shark (got 6 for 30 bucks on sale) for exhaust, the Noctua running at 1200 RPM and the Shark at a mere 700. Every month I open the case and wipe the bottom and edges. Only every 4 months do I need to dust off components.

[spwath]

The point of positive air pressure it to make dust gravitate to the edges and corners of the case instead of to the components. There is a sweet spot to maintain flow through the case while still letting dust fall to the floor, and it's different with every case. For my Lian Li it's 12 CFM extra going in than out supported by a Noctua Nf F12 for intake and a cheap aerocool shark (got 6 for 30 bucks on sale) for exhaust, the Noctua running at 1200 RPM and the Shark at a mere 700. Every month I open the case and wipe the bottom and edges. Only every 4 months do I need to dust off components.

That's not really correct. Positive is to draw the air through the filters.

[patrickjp93]

That's not really correct. Positive is to draw the air through the filters.

No, that is the point of STATIC pressure-optimized fans. The point of a positive pressure case configuration is to keep dust away from the components.

[spwath]

No, that is the point of STATIC pressure-optimized fans. The point of a positive pressure case configuration is to keep dust away from the components.

No. Static pressure optimized is just to get through restrictive things like radiators

[patrickjp93]

No. Static pressure optimized is just to get through restrictive things like radiators

And fine filters...

 

Take the aerocool sharks as an example with 82.6 CFM rating but 0.xx static pressure. You put any sort of filter in front of it you'll be lucky to get 30 CFM.

[spwath]

And fine filters...

Yeah, so?

Static pressure fans are for filters, not denying that.

[patrickjp93]

Yeah, so?

Static pressure fans are for filters, not denying that.

Positive pressure and static pressure are different concepts, and positive pressure has nothing to do with filters. It has to do with particle distributions in the air currents. Some dust gets shoved to the sides immediately as air enters a case because it's a large object which interacts differently from the molecules of air. As air tries to find an escape route it goes for any cracks in the case, namely the corners and edges, dragging the dust with it. Too much positive pressure and you get no linear flow. Not enough and you'll have dust covering all the main components on the way to the exhaust fans.

[spwath]

Positive pressure and static pressure are different concepts, and positive pressure has nothing to do with filters. It has to do with particle distributions in the air currents. Some dust gets shoved to the sides immediately as air enters a case because it's a large object which interacts differently from the molecules of air. As air tries to find an escape route it goes for any cracks in the case, namely the corners and edges, dragging the dust with it. Too much positive pressure and you get no linear flow. Not enough and you'll have dust covering all the main components on the way to the exhaust fans.

They are different concepts, and positive pressure does have nothing to do with filters.

POsitive pressure means there is more intake than exhaust, so the pressure is slightly higher inside the case.

You do this because then the air only goes in through the filtered intakes. Air escapes through cracks and holes, instead of going in thorugh them.

This causes less dust.

 

What you are saying is not really right at all.

[patrickjp93]

They are different concepts, and positive pressure does have nothing to do with filters.

POsitive pressure means there is more intake than exhaust, so the pressure is slightly higher inside the case.

You do this because then the air only goes in through the filtered intakes. Air escapes through cracks and holes, instead of going in thorugh them.

This causes less dust.

 

What you are saying is not really right at all.

You literally reworded exactly what I said with less detail. Reread my post because we just agreed 100%

[andersdog]

You literally reworded exactly what I said with less detail. Reread my post because we just agreed 100%

He's referring to the implied contrary scenario -- when there's negative pressure then dust is pulled in through the unfiltered crevices, vents, grills, etc. So, positive pressure with filtered intakes resolves this scenario. Nothing gets sucked in, because there is no low pressure system for them to be pulled into.

You're referring to the (finer, if you're using filters) particulates that get in anyway, and how they interact in high or low pressure airflow scenarios. Which is different -- but also interesting, because I hadn't considered that side of things.

[spwath]

You literally reworded exactly what I said with less detail. Reread my post because we just agreed 100%

You said something about how air moves around an object

[LogicalDrm]

Positive pressure and static pressure are different concepts, and positive pressure has nothing to do with filters. It has to do with particle distributions in the air currents. Some dust gets shoved to the sides immediately as air enters a case because it's a large object which interacts differently from the molecules of air. As air tries to find an escape route it goes for any cracks in the case, namely the corners and edges, dragging the dust with it. Too much positive pressure and you get no linear flow. Not enough and you'll have dust covering all the main components on the way to the exhaust fans.

 

You got something messed there.

 

Yes. Positive pressure and static pressure are different things. But not like you say. You can have positive air pressure and you can use static pressure fans to achieve it. Static pressure fans are build to blow air in tower shape column. This is good for using them with rads. The other type of fan would be airflow where fan blows air to fan (no pun intended) shape column. Which is good when you want air to go many places. Intakes are usually these.

 

Positive, negative and neutral air pressure are about what pressure inside the case in general is. This is managed by how much intake and exhaust are. The key is CFM for combined intake and exhaust respectively. While case has positive air pressure, dust is gathered mainly on filters in front of intake fans and doesn't come in from anywhere else. While on negative air pressure, dust will come inside the case anywhere where there isn't filters. Neutral is somewhere between these. I don't know about how smaller particles go around or how much effect they have. I also don't know how dust moves inside the case. Those things don't really have matter to me. My case gathers very little dust from unfiltered mesh anyway.

[patrickjp93]

You got something messed there.

 

Yes. Positive pressure and static pressure are different things. But not like you say. You can have positive air pressure and you can use static pressure fans to achieve it. Static pressure fans are build to blow air in tower shape column. This is good for using them with rads. The other type of fan would be airflow where fan blows air to fan (no pun intended) shape column. Which is good when you want air to go many places. Intakes are usually these.

 

Positive, negative and neutral air pressure are about what pressure inside the case in general is. This is managed by how much intake and exhaust are. The key is CFM for combined intake and exhaust respectively. While case has positive air pressure, dust is gathered mainly on filters in front of intake fans and doesn't come in from anywhere else. While on negative air pressure, dust will come inside the case anywhere where there isn't filters. Neutral is somewhere between these. I don't know about how smaller particles go around or how much effect they have. I also don't know how dust moves inside the case. Those things don't really have matter to me. My case gathers very little dust from unfiltered mesh anyway.

That is what I said with a little more detail on CFM...

[LogicalDrm]

That is what I said with a little more detail on CFM...

 

Well... then I quoted wrong post since you had bit different opinion earlier.

[spwath]

Well... then I quoted wrong post since you had bit different opinion earlier.

yEAH, he was saying something that was wrong before, but when i said the right thing, he said i just reworded what he said.

[patrickjp93]

yEAH, he was saying something that was wrong before, but when i said the right thing, he said i just reworded what he said.

I said nothing wrong. All you changed was where you concentrated the details of the argument.

 

What was wrong?

[LogicalDrm]

@patrickjp93, this is the thing:

 

No, that is the point of STATIC pressure-optimized fans. The point of a positive pressure case configuration is to keep dust away from the components.

 

That is messed. I don't know about dust falling optimized config. That isn't really any major thing to consider. And even if it would be, there are times when system is powered down and dust will fall in from top mesh anyway.

[patrickjp93]

@patrickjp93, this is the thing:

 

That is messed. I don't know about dust falling optimized config. That isn't really any major thing to consider. And even if it would be, there are times when system is powered down and dust will fall in from top mesh anyway.

I've never owned a case with a top mesh so I can't say, and this is exactly what your explanation agrees with. Dust gets drawn through the filter(s) but not the sides, and in fact dust gets pushed to the sides due to non-newtonian fluid dynamics. That is the point of positive pressure builds: keep dust out and away from the central components. It's a natural consequence of everything else.

[spwath]

I've never owned a case with a top mesh so I can't say, and this is exactly what your explanation agrees with. Dust gets drawn through the filter(s) but not the sides, and in fact dust gets pushed to the sides due to non-newtonian fluid dynamics. That is the point of positive pressure builds: keep dust out and away from the central components. It's a natural consequence of everything else.

That is wrong. Positive pressure is not to push dust away from components, its to prevent dust from getting in at all. What you are saying is incorect.

[patrickjp93]

That is wrong. Positive pressure is not to push dust away from components, its to prevent dust from getting in at all. What you are saying is incorect.

oh dear lord that is semantics. It's entirely correct! Push any dust drawn in through the front to the sides, and keep dust from slipping in through the cracks. It's exactly the same idea!

[LogicalDrm]

I've never owned a case with a top mesh so I can't say, and this is exactly what your explanation agrees with. Dust gets drawn through the filter(s) but not the sides, and in fact dust gets pushed to the sides due to non-newtonian fluid dynamics. That is the point of positive pressure builds: keep dust out and away from the central components. It's a natural consequence of everything else.

 

If you could draw pic to demonstrate this? My knowledge of physics isn't the best but I can get Masters level physicist to verify this. AFAIK you are partly right there. Dust gets drawn into filters. Thats what they are for. Every fan that is sucking air will suck dust with it. I think your own sayings are conflicting there since dust/air can't be pulled through filters same time as they are pushed around them. That just makes no sense. If you'd want to keep dust away from components, you'd need to position fans so that they blow air away from those components. Which isn't such effective method of cooling as seen with stock cooler. Well, LP coolers are exception but they also need intake fans to provide fresh air. Which would be blowing dust towards those components.