howardpm Posted December 1, 2010 Share Posted December 1, 2010 I'm building a new machine and purchased both the Corsair 600t and the Corsair AX850. I noticed the p/s can be mounted fan up or fan down. There is a grate at the bottom of the face, I assume to let air escape. Do people recommend facing the fan up or down? Is there enough clearance below the case so the heat escapes (even with my face against a wall. Link to comment Share on other sites More sharing options...
Carlos68 Posted December 1, 2010 Share Posted December 1, 2010 I'm building a new machine and purchased both the Corsair 600t and the Corsair AX850. I noticed the p/s can be mounted fan up or fan down. There is a grate at the bottom of the face, I assume to let air escape. Do people recommend facing the fan up or down? Is there enough clearance below the case so the heat escapes (even with my face against a wall. The vent at the bottom of the case is to allow air into the PSU which is then vented out the back of the PSU. So it needs to be mounted with the fan facing down ! Link to comment Share on other sites More sharing options...
abisel Posted December 7, 2010 Share Posted December 7, 2010 Cases with bottom mounted PSU's were designed with having the PSU fan down to draw air from outside the case. However, the space between the PSU and the floor/table is only an inch and may impede air flow. If you have the case on the floor, the PSU will act like a vaccum cleaner and suck up the dust, lint, cat hair, dog hair, dust bunnies, etc. All that being said, I mounted my PSU with the fan up. Also, with the PSU mounted fan down, there would be some radiated heat into the case. With the PSU mounted fan up, the fan would suck that radiated heat and exhaust it out the case. JHMO, but mount the PSU fan up. Link to comment Share on other sites More sharing options...
Corsair Employees RAM GUY Posted December 8, 2010 Corsair Employees Share Posted December 8, 2010 Cases with bottom mounted PSU's were designed with having the PSU fan down to draw air from outside the case. However, the space between the PSU and the floor/table is only an inch and may impede air flow. If you have the case on the floor, the PSU will act like a vaccum cleaner and suck up the dust, lint, cat hair, dog hair, dust bunnies, etc. All that being said, I mounted my PSU with the fan up. Also, with the PSU mounted fan down, there would be some radiated heat into the case. With the PSU mounted fan up, the fan would suck that radiated heat and exhaust it out the case. JHMO, but mount the PSU fan up. Anything more than a few mm of space between the PSU and the floor should not have any problems with airflow. There is a dust filter installed below the PSU in the 600T so dust should not be an issue. Ultimately you can mount the PSU with the fan facing up or down, but I have installed the PSU with the fan facing down in every build that I have done with our cases and I have never had any problems. Link to comment Share on other sites More sharing options...
Carlos68 Posted December 8, 2010 Share Posted December 8, 2010 The other problem with mounting the fan facing up is that it will efffect the air flow inside the case, as the cool air coming in through the front and only input fan will be drawn down and straight out instead of passing over the hot components and vented out the top !! Link to comment Share on other sites More sharing options...
abisel Posted December 9, 2010 Share Posted December 9, 2010 With the PSU mounted fan up, it will draw some, I repeat, some of the intake fan airflow, but not as much as you may think. The PSU fan runs pretty slow most of the time unless you have multiple graphics cards and such. And with the HDD cage behind the intake fan, that disrupts the air flow. Also, think about the cases where the PSU is mounted at the top where the fan is facing down drawing air from within the case. If you are still worried that the PSU fan will draw too much of the intake fan airflow, you can build a baffle or such to mount in front of the PSU so that intake fan airflow is directed upward. Some cases have a shelf/shield that is mounted above the PSU. I still favor mounting the PSU fan up and I do plan to increase the intake fan airflow by upgrading the intake fan to 800rpm at 76cfm. The stock fans only run at 550 and have a lower cfm (does anyone know the specs of the stock fans?) Link to comment Share on other sites More sharing options...
Carlos68 Posted December 9, 2010 Share Posted December 9, 2010 With the PSU mounted fan up, it will draw some, I repeat, some of the intake fan airflow, but not as much as you may think. The PSU fan runs pretty slow most of the time unless you have multiple graphics cards and such. And with the HDD cage behind the intake fan, that disrupts the air flow. Also, think about the cases where the PSU is mounted at the top where the fan is facing down drawing air from within the case. If you are still worried that the PSU fan will draw too much of the intake fan airflow, you can build a baffle or such to mount in front of the PSU so that intake fan airflow is directed upward. Some cases have a shelf/shield that is mounted above the PSU. I still favor mounting the PSU fan up and I do plan to increase the intake fan airflow by upgrading the intake fan to 800rpm at 76cfm. The stock fans only run at 550 and have a lower cfm (does anyone know the specs of the stock fans?) The stock fans are 800rpm and 76cfm and that means they limit the air input already and adding the PSU drawing air back out then that will effect the cooling of the case. Also the cases where the PSU is at the top drawing air out, well thats the idea as hot air rises inside the case ;): Link to comment Share on other sites More sharing options...
abisel Posted December 12, 2010 Share Posted December 12, 2010 The stock fans are 800rpm and 76cfm and that means they limit the air input already and adding the PSU drawing air back out then that will effect the cooling of the case. Also the cases where the PSU is at the top drawing air out, well thats the idea as hot air rises inside the case ;): Carlos, I respect your opinion but it doesn't hold water. You said that if the PSU at the bottom draws air from inside the case, it would affect cooling inside the case. That is true. It would help. Then you said if the PSU is mounted at the top, that design would draw hot air from inside the case. Again true, but in both situations you get the same result. Don't forget, the 600T (and a lot of other cases) have the top 200mm fan exhausting hot air. Bottom line, it doesn't matter which way you orient the bottom PSU fan. It is up to the owner/builder. You seem to be adamant with the necessity to mount the bottom PSU fan down. I would like to see some real numbers on this issue. Let’s see some benchmarks about airflow within the case, temps within the case. Maybe Yellowbeard can step in. If I’m wrong about this, I’ll be first to apologize. My PC isn’t some extreme gamer, but then again, it never gets hot. My case is the 600T and I have a Corsair AX850 mounted with the fan up. The front and top case fans never get above 600rpm, and the rear fan never gets above 850rpm. And after running Black Ops for an hour, the CPU or GPU temps never get above 58C (their fans do respond to demand). The PSU fan never spins up either. So my computer is running just fine with the PSU fan up. Link to comment Share on other sites More sharing options...
Synthohol Posted December 12, 2010 Share Posted December 12, 2010 i have to say this is a funny debate. up or down is of no consequence IMHO, however to simply add my unsolicited .02, the 600t has a large air inlet on the bottom under the PSU so being airflow takes the path of least resistance, it makes more sense (in this case) to install the PSU fan down as to cause as little case airflow disruption as possible as the majority of the air supply will be drawn from beneath the case into the PSU (the path of least resistance) thereby affecting the path of fresh air drawn in by design. i doubt the engineers of the 600t would have overlooked this "chicken or the egg / PSU up or down" scenario. i wont even go into detail about the vortex's created by the GPU card fans that rarely run at 100% anyway whereas "redirected" passive airflow may just slightly affect the volume of air drawn into the GPU fan vortex. frankly i believe this is a mute point and aesthetics is the stronger point to consider in this matter. Link to comment Share on other sites More sharing options...
TrailTrackers Posted January 2, 2016 Share Posted January 2, 2016 Geeze... I came here for some advice because I had the same question concerning the AX 1500i. And all I found was the same 'ole arguments that I've read on every other hit Google gave me. I'll go with the "it makes no difference" advice since I have it mounted fan down, and I don't want to 'create' work for myself. I also see the last comment before mine was in 2010. Link to comment Share on other sites More sharing options...
abisel Posted January 2, 2016 Share Posted January 2, 2016 ... and I thought this thread was dead. I did find that with the placement of the PSU at the bottom of the case, air flow is blocked when the computer is placed on carpet no matter which way the PSU is mounted. So although it is true it doesn't matter which way the PSU is mounted, if the airflow is blocked by carpet, consideration should be made to raise the computer. I went to the local hardware store and got some small furniture casters and modified the computer case. Makes it easier to move around too. Cheers, Link to comment Share on other sites More sharing options...
svliegen Posted January 8, 2016 Share Posted January 8, 2016 I have a Corsair RM650X which I am about to install in a Fractal Design Define R5 case. It will be installed at the bottom, where the case has suitable vents. Initially I was planning to install the PSU fan-down. However, since the PSU fan will rarely spin, wouldn't that cause the PSU to run hotter than when it is installed fan-up? Fan-up, the heat could exit at the top through natural convection, as long as the fan is not spinning. But that would make the case temperature go up. What do you guys think? Link to comment Share on other sites More sharing options...
Datakiller24 Posted January 9, 2016 Share Posted January 9, 2016 Hi, I have the same case like You, 1000W PSU mounted fan down (as the case manual also recommends). As the PSU is warming up (even in passive mode) the air it creates natural circulation of the air (so cold from the bottom will go inside as the warm air finds it´s way out in the back). The case stands are high enough, opening are big enough so don´t be affraid, install it fan down. BR, Peter Link to comment Share on other sites More sharing options...
TBrandes Posted January 12, 2016 Share Posted January 12, 2016 This 'natural convection' is totally overrated. In a small space (aka PC) a single fan (like one in the back) will almost always disrupt this process as it causes an airflow which is much stronger than the effect of the convection. If you have two fans (for example front and back) you don't have to worry about that anymore. Link to comment Share on other sites More sharing options...
Datakiller24 Posted January 13, 2016 Share Posted January 13, 2016 This 'natural convection' is totally overrated. In a small space (aka PC) a single fan (like one in the back) will almost always disrupt this process as it causes an airflow which is much stronger than the effect of the convection. If you have two fans (for example front and back) you don't have to worry about that anymore. Hi, If the PSU is mounted fan down than there is no influence from inside the case (the PSU radiates some "minimal" heat inside but it´s closed box so the fans mounted to the case ... makes no sense). And the question comes, if I can avoid to put more heat into the case, why not to avoid it (intake from bottom, exhaust at the back "fan down mount")? Also, no fan used for cooling up to some load level means less noise (it´s valid for semi-passive PSU-s). Same applies when the fan is running and cooling the PSU with colder air, so must run at lower rpm (longer lifetime, smaller noise). If the case has bottom filter than the mounting orientation is no question ;) BR, Peter Link to comment Share on other sites More sharing options...
TBrandes Posted January 13, 2016 Share Posted January 13, 2016 I wasn't talking about any PSU or the position of it - i was talking about 'natural convection'. ;) This always comes up when people talk about cases or temperatures in a PC. But most of the time they ignore or don't know the physics behind it. Link to comment Share on other sites More sharing options...
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