Confused about aftermarket GPU coolers

[Drakonath]

I see all these after market gpu's with like 2-3 fans on them. Doesn't that completely ruin air flow in a case?

Assuming normal GPU orientation with the fans facing downwards. Which way do the fans blow? Where does the card direct the air? I am very confused and there seems to be no good information regarding this.

Can anyone break it down please?

 

[TJ Hooker]

They pull air upwards, through the cooler's heatsink fins, with the air being expelled around the edges of the card and out the rear vents.

 

[Drakonath]

They pull air upwards, through the cooler's heatsink fins, with the air being expelled around the edges of the card and out the rear vents.

So it directs air towards the top of the case, more or less?

 

[Karadjgne]

Sort of, it more blows the exhaust heat sideways, where natural thermal properties will make the heated air rise. One of the reasons why case intake fans need to be low, the intakes push the air in below the gpu, some of it rotating up but most is sucked in by the vacuum created by the gpu fans. With the vacuum created by the top rear exhaust fans at the top-rear of the case, everything is basically designed to shunt gpu air straight up. And out. What'll really disrupt case airflow is side mounted fans used as intakes by ppl believing air blown onto the gpu would be a good thing. Just the opposite. Use side fans as exhaust. As close as the gpu edges are to the case side, side exhaust does well to trap that and exhaust it out directly. Works the same theory as a tower air cooler and rear exhaust. Just need to maintain considerably higher intake than side exhaust, or not much makes it upto the cpu cooler.

Fans have 2 distinct sides. One side is all fan blades, nice and neat, that's the pretty side. The other side shows the back of the motor housing, support stems, wires. That's the ugly side. Air is moved from pretty to ugly. A fan works by spinning, which creates a vacuum on the pretty side, which pulls in surrounding air, which is then exhausted out the ugly side. Certain blade designs create higher volume and a harder exhaust push, these are high static pressure fans. Other blade designs spin much faster to create the higher vacuum, so have a greater exhaust. These are higher cfm fans. Some fans are balanced between the 2 designs, so end up with more moderate cfm and sp. With gpu oriented fans facing pretty side towards the floor, they are oriented to draw in cooler air from below, forcing fan exhaust across the gpu heatsinks, which then escapes out the side facing the open area. Hot air rises, helped along by excess intake and top fan vacuum.

 

[ddferrari]

Wow, a lot of wrong answers here.

1. If fans on GPUs ruined case's air flows, they wouldn't be designed that way.
2. On virtually every consumer-grade GPU in the past and present, the fans on the GPU (unless rear exhausting) face DOWN, not up. They blow air toward the bottom of the case. There is no way to "flip them over", either.
3. Air flow isn't that complicated in a small box; wherever it is aimed initially, it will make its way out through the exhaust fans at the rear/top. The intake fans in the front/side of the case (if present) don't just blow in cool air in, they create air pressure in the case. This forces the air out through the top/back. Heat always rises.
4. Side fans are always meant to be INTAKES according to the experts AND case manufacturers. Don't you think the companies that design cases have tested every scenario and measured the air flow results?
5. I have TWO GPUs (SLI) in my system, each with three fans (Gigabyte 670 OC) with a side intake fan and they never go over 68° C during the heaviest gaming, well within their temperature specs.

 

[Karadjgne]

Be careful slinging around that epitaph 'a lot of wrong answers'. Intake fans do not do much at all for what most ppl would consider 'air pressure. Air pressure itself is 14.7lbs/in². What you are calling' positive pressure' is closer to 14.7001 lbs/in² and 'negative pressure' would be 14.6999 lbs/in². That's about enough difference to affect the microparticulate dust and thats about all. There's far too many vents, gaps, fan slots, grills etc for there to be any consistency in airflow or for pressure to have any affect.
Take a good look at a case, any case with side fan vents. None have dust filters. Even cases claiming to have full dust filtration do not have filters on side vents. They are meant to be used as exhaust, not intake. The only time those side vents were used as intake was on old AT cases and first gen ATX before case designs really took cooling cpus a little more seriously. Cases are all about cooling the cpu, because that's general to every pc, large, hot gpus are not present in every case.
Using side fans as intakes keeps warmer air inside the case, putting more emphasis on the cpu heatsink. As you say, heat rises, you might have cooler running gpus, but the cpu suffers as a result. Flip those fans around and the top gpu will see less of an impact from the exhaust of the bottom gpu, and cpu temps at load will be lower.
Heat rises, that's a given, but if you want to see the effect airflow has on heat, light a cigarette, hold it upright and look at the smoke trail. Goes up pretty solid, all by itself. Now blow across the top of the cherry, the smoke goes everywhere. This is what happens to natural thermal conduction with the introduction of a side fan. You blow the gpu exhaust heat throughout the case. Some goes out, most doesn't make it that far and gets recirculated back to the gpu/cpu intakes. Now try sucking air across the top of the cherry. Smoke pretty much goes with the airflow, most will make a 90° turn. That's what happens when the fan is used as exhaust.
Better by far to use side vents as exhaust unless gpu temps are so out of control that they require the fans used as intakes.
Nature abhors a vacuum, air will always flow naturally from higher to lower pressure, there's no force involved.

This from an expert btw.

Edit: oh and BTW, gpu fans face down, but blow air upwards into the gpu, not down to the case bottom, might wanna rethink that statement.

 

[ddferrari]

Yes, I can tell that you're an "expert"... and when someone asks you for the time, you undoubtedly proceed to instruct them on how to build a clock. You must be the life of the party.

"Take a good look at a case, any case with side fan vents. None have dust filters."

Again, incorrect. My Antec 902 V3 has a dust filter for the side fan. I pull it out and clean it every few months. BTW, Antec's owner manual stated that the fan should be set up for intake. I'll take their word over yours any day.

 

[Karadjgne]

https://youtu.be/f6snWfd1v7M

Funny how all those psu's made claims to wattage (you'd think they'd know how a psu was built and what it'd actually do) yet reality proved them sadly mistaken. You'll find that there's a lot of stuff in the instructions, materials, claims that's useless, pointless or downright lies, most of it is a selling point to influence the ignorant. A gimmick. Why do you think most gpus come with that snazzy little molex-pcie adapter. The 'experts' included it, so you should use it, right? Hell, even my car specifies I should be using Dex-Cool in the radiator (right? Even though it's known to cause more failures and issues than plain water). I guess it never occurred to you that since they are selling a case in a market that's stifled with hundreds of others, adding a dust filter in the side might be nothing more than a selling point, so on the instructions they specify it to be used as an intake (that's called justification). Speed limits in the US were 55mph, the lawmakers claimed it was for safety reasons. Bunch of crap. It was set there in 1972 by the US govt because 55mph was the most fuel efficient speed for those gas guzzling, 10mpg v8 vehicles. (ppl back then could care less about fuel efficiency, safety is another beast altogether)

Should I go on? Manufacturer claims and instructions are only as good as the paper they are printed on. Truth is rarely a concept they specialize in.

 

[TJ Hooker]

2. On virtually every consumer-grade GPU in the past and present, the fans on the GPU (unless rear exhausting) face DOWN, not up. They blow air toward the bottom of the case. There is no way to "flip them over", either.

Yes, the fans face down. No, they don't blow air toward the bottom of the case. They pull air upwards.

Edit: E.g. http://www.gigabyte.com/FileUpload/Global/KeyFeature/503/img/2.jpg

 

[ddferrari]

https://youtu.be/f6snWfd1v7M

Funny how all those psu's made claims to wattage (you'd think they'd know how a psu was built and what it'd actually do) yet reality proved them sadly mistaken. You'll find that there's a lot of stuff in the instructions, materials, claims that's useless, pointless or downright lies, most of it is a selling point to influence the ignorant. A gimmick. Why do you think most gpus come with that snazzy little molex-pcie adapter. The 'experts' included it, so you should use it, right? Hell, even my car specifies I should be using Dex-Cool in the radiator (right? Even though it's known to cause more failures and issues than plain water). I guess it never occurred to you that since they are selling a case in a market that's stifled with hundreds of others, adding a dust filter in the side might be nothing more than a selling point, so on the instructions they specify it to be used as an intake (that's called justification). Speed limits in the US were 55mph, the lawmakers claimed it was for safety reasons. Bunch of crap. It was set there in 1972 by the US govt because 55mph was the most fuel efficient speed for those gas guzzling, 10mpg v8 vehicles. (ppl back then could care less about fuel efficiency, safety is another beast altogether)

Should I go on? Manufacturer claims and instructions are only as good as the paper they are printed on. Truth is rarely a concept they specialize in.

Wow- nice off-topic rant. Paranoid much?

What benefit or "selling point"- in your mind - would the mfr gain by telling people to set up side fans as exhaust, with or without a filter? What would they gain by doing that? Nothing- because you don't get the instruction manual until you buy the case. They already made the sale. There's nothing to gain by "lying" at that point. I didn't buy my case based on the side fan filter anyway, no one does. I bought it for the looks, interior space, and cooling- like 99% of all buyers. You seem to think mfrs charge a premium for that filter. Might want to loosen the tin foil hat a little, son. You're a mess.

"I guess it never occurred to you that since they are selling a case in a market that's stifled with hundreds of others, adding a dust filter in the side might be nothing more than a selling point, so on the instructions they specify it to be used as an intake (that's called justification)."

What a joke. I guess you're not man enough to admit that I just proved you wrong- as obviously some cases DO come with side fan filters. As a self proclaimed "expert" I thought you'd know this. Are you actually suggesting that I should take your Joe-blow-on-a-forum word over all the tech sites and mfr's advice about air flow direction? Forget it pal; despite what mom may have told you, you're not that special. And if you're an "expert", then God help us all.

 

[Karadjgne]

Don't call me son, I'm probably older than you. Haven't spoken to Mom much in the last 20 years or so, so I wouldn't know that either.
Anyone buying a case doesn't do it blind, they'll look at it first, read the info online, read the Amazon junk etc so no, not the install directions as you assume, until they do buy the case and it tells them that because they bought a case with a side dust filter (which 98% of cases don't include) that it should be used as intake. It's no different than some cases use red leds as intake fans, you'll see it in the pictures, you'll see it printed 'comes with led fans!', like that really makes a difference, it's just something to distinguish the case from others, a selling point.
And yes, I actually did dig up the manual on my old CoolerMaster 690 II Advanced and it says quite clearly that because the 2x fan slots on the case side are unfiltered they should be used as exhaust.

Nzxt H440, has 3x 120mm intakes in the front, written in every advertisement you see that because of its 3 fans it has excellent airflow and cooling properties. That's the manufacturer talking. Reality is the H440 has pretty mediocre airflow and cooling properties. That's the expert reviews and pretty much everyone other than the manufacturer. Just because a manufacturer makes claims, doesn't mean they are gospel. And shouldn't be taken as the full truth. Side fan vents should be used as exhaust in most pc's, unless they are filtered for intake or the gpus temps are far out of control otherwise.

My grandfather was a 'prop man' in WWII, my father is a flight mechanics engineer, and I'm a retired fire-fighter/arson investigator, so I've been around airflow and thermal dynamics, it's patterns and properties my whole life. I'm not an expert because I'm some Joe-Blow-on-a-forum who read it in a post, I'm an expert because I am.

 

[ddferrari]

Don't call me son, I'm probably older than you. Haven't spoken to Mom much in the last 20 years or so, so I wouldn't know that either.
Anyone buying a case doesn't do it blind, they'll look at it first, read the info online, read the Amazon junk etc so no, not the install directions as you assume, until they do buy the case and it tells them that because they bought a case with a side dust filter (which 98% of cases don't include) that it should be used as intake. It's no different than some cases use red leds as intake fans, you'll see it in the pictures, you'll see it printed 'comes with led fans!', like that really makes a difference, it's just something to distinguish the case from others, a selling point.
And yes, I actually did dig up the manual on my old CoolerMaster 690 II Advanced and it says quite clearly that because the 2x fan slots on the case side are unfiltered they should be used as exhaust.

Nzxt H440, has 3x 120mm intakes in the front, written in every advertisement you see that because of its 3 fans it has excellent airflow and cooling properties. That's the manufacturer talking. Reality is the H440 has pretty mediocre airflow and cooling properties. That's the expert reviews and pretty much everyone other than the manufacturer. Just because a manufacturer makes claims, doesn't mean they are gospel. And shouldn't be taken as the full truth. Side fan vents should be used as exhaust in most pc's, unless they are filtered for intake or the gpus temps are far out of control otherwise.

My grandfather was a 'prop man' in WWII, my father is a flight mechanics engineer, and I'm a retired fire-fighter/arson investigator, so I've been around airflow and thermal dynamics, it's patterns and properties my whole life. I'm not an expert because I'm some Joe-Blow-on-a-forum who read it in a post, I'm an expert because I am.

I repeat: I'm not taking your word over the advice of well respected companies who employ engineers that design and build cases for a living, in a highly competitive industry.

You are aware that the dust filters are removable, correct? Therefore, the mfr has no reason to give the wrong advice on airflow, they would simply state that if using the fan as exhaust then leave the filter out. There's no industry-wide conspiracy to sell more cases by lying about airflow or luring the stupid masses to buy their case through this "gimmick" (as you say) called a side air filter. So a side filter is a gimmick, but front air filters aren't? 😵

If exhaust was the correct direction, why would any of them bother with filters at all? It costs them money to include them, but I highly doubt my case would have been one penny cheaper even if it didn't come with it. While being an arson investigator may have given you some knowledge about airflow, it does not make you a computer case expert. You also seem to imply a lot that pretty much everyone in the industry is dishonest. Glad I'm not living in your world; you seem so paranoid of being duped that you just preemptively distrust everyone.

Tell you what: I just pulled the trigger on a new 1080 Ti and should have it by the weekend. When I install it I'll reverse my side fan to exhaust (and remove the filter). I'll game on it for an evening and then turn the fan around and game on it again for an evening, closely monitoring temps. I'll come back and report the results- no matter what they show. I doubt you'll accept the results if they support my argument anyway, but it gives me a good excuse to watch my temps on the new gpu.

 

[bishopi5]

Please Stop

 

[ddferrari]

Please Stop

Why don't you just unfollow the thread if this upsetting you so? Probably a better solution than trying to impose your will on complete strangers.

 

[bishopi5]

How about you stop talking? like you should have done as soon karad proved you wrong the very first post he made. You literally have no idea what you're talking about yet you keep typing, stop wasting karad's time. All you have done is derail the thread completely because you can't admit you are wrong.

 

[ddferrari]

How about you stop talking? like you should have done as soon karad proved you wrong the very first post he made. You literally have no idea what you're talking about yet you keep typing, stop wasting karad's time. All you have done is derail the thread completely because you can't admit you are wrong.

How about you buzz off, Tinkerbell? No one asked for your opinion, and this convo isn't derailing the thread at all- it's about airflow and that's exactly what we're talking about (WE- not YOU).

Seriously, get lost and grab a box of tissues on your way out.

PS: Just reported you for hijacking the thread

 

[Deleted member 217926]

Thank you for alerting the mod team to....you. The only person I see going out of their way to call people names and be unjustifiably rude is you ddferrari. So tone it down.

 

[Deleted member 217926]

2. On virtually every consumer-grade GPU in the past and present, the fans on the GPU (unless rear exhausting) face DOWN, not up. They blow air toward the bottom of the case. There is no way to "flip them over", either.

Yeah, no. They face down yes, and blow air through the graphics card. They blow air toward the top of the case not the bottom....they use thermodynamics to their advantage, heat rises.....graphics cards don't use the 'pull' configuration.


Now admittedly a card with a backplate is going to diffuse that air and not allow it to flow upwards freely but those fans aren't blowing down.

 

[Deleted member 217926]

Also front, side and bottom fans are intake. My NZXT Phantom 820 has a side filter as did my old Antec 1200. Top and rear fans are exhaust.

 

[bishopi5]

Don't waste you're time anort3 !

 

[Someone Somewhere]

2. On virtually every consumer-grade GPU in the past and present, the fans on the GPU (unless rear exhausting) face DOWN, not up. They blow air toward the bottom of the case. There is no way to "flip them over", either.

Yeah, no. They face down yes, and blow air through the graphics card. They blow air toward the top of the case not the bottom....they use thermodynamics to their advantage, heat rises.....graphics cards don't use the 'pull' configuration.


Now admittedly a card with a backplate is going to diffuse that air and not allow it to flow upwards freely but those fans aren't blowing down.

Forget about the backplate; PCBs tend to be pretty good at blocking air.

My understanding is that most of the air goes towards your side panel, away from the motherboard.

 

[ddferrari]

Don't waste you're time anort3 !

Did you even read anort3's reply, let alone my posts?

"Also front, side and bottom fans are intake."

That's what I've been saying in every one of my posts.

 

[ddferrari]

Thank you for alerting the mod team to....you. The only person I see going out of their way to call people names and be unjustifiably rude is you ddferrari. So tone it down.

The irony here is not lost on me- especially the use of a snarky tone to tell me to stop being snarky! :lol: