Tsyras Posted February 16, 2016 Share Posted February 16, 2016 I am about to be purchasing a 750D (non-airflow...love the aesthetic of the original case) along with a H115i (seems this is identical to the H110i GTX). I will be replacing the H115i fans with Noctua 2000 RPM PWM fans. In addition, I will be replacing the rear fan with the same Noctua. I will also be adding 2x 2000 RPM 120mm Noctuas at the bottom for intake. For intake I will have the stock 140s up front, dual 120 Noctuas on the bottom, and I want the H115i configured for intake. The rear fan will be the only exhaust. 1) Does this sound reasonable? 2) Is the top mesh suitable to prevent intake dust? 3) Would something like the following linked dust filter be enough to prevent dust on the bottom 120mms? http://www.amazon.com/Silverstone-Filter-Magnet-Cooling-FF123B/dp/B00ARB5E8U/ref=sr_1_1?ie=UTF8&qid=1455663022&sr=8-1&keywords=120mm+dust+filter 4) Is there anything else I can do to help control dust? 5) I presume adding another 140mm for intake at the top would be complete overkill? I had thought about using the radiator as exhaust and adding a 140mm as intake at the top, but being right next to the radiator exhaust I thought that may cause some turbulence issues. Link to comment Share on other sites More sharing options...
snapper69 Posted February 17, 2016 Share Posted February 17, 2016 I'm all for a slightly positive pressure, but it seems to me that in your case, the air will have nowhere to go, so you will probably end up with it overheating due to no circulation. You would be better having the H115i as an exhaust ( it should only make a couple of degrees difference to your cpu and the other components will thank you for it) the rear fan as an exhaust and all the other fans as intake. Link to comment Share on other sites More sharing options...
Tsyras Posted February 17, 2016 Author Share Posted February 17, 2016 Thanks for the reply. The problem with that is the front panel is constrictive enough I think that would result in negative pressure unless I really want to dial back the exhaust fan RPMs, which directly affects CPU temp. What if I did do this and added another 140mm intake on the top? I just am not sure how well having both exhaust and intake on the top will affect things. Link to comment Share on other sites More sharing options...
Tsyras Posted February 18, 2016 Author Share Posted February 18, 2016 Thanks for the reply. The problem with that is the front panel is constrictive enough I think that would result in negative pressure unless I really want to dial back the exhaust fan RPMs, which directly affects CPU temp. What if I did do this and added another 140mm intake on the top? I just am not sure how well having both exhaust and intake on the top will affect things. So...I just read that the top will only support 3 120s or 2 140s. Since I have a 240 radiator coming it sounds like I won't be able to do my plan. So I shelled out another $27 for 4th 2000 rpm Noctua to replace to front 2 fans as well. The last time I bought a case was April 2010, so if I get ~6 years out of this setup I am fine with the extra up front costs. To help generate the positive airflow I want, I did purchase the $15 airflow grill, and will just put back on the normal grill when I have guests come over! :p: Link to comment Share on other sites More sharing options...
snapper69 Posted February 19, 2016 Share Posted February 19, 2016 You could have tried to get hold of the Airflow front panel for the 750D. I had a 750 D a bit back and taking the front panel off didn't drop the temps that much (about 3 degrees as I recall) The dual Noctuas on the bottom should more than make up for any restriction caused by the front panel. Link to comment Share on other sites More sharing options...
c-attack Posted February 22, 2016 Share Posted February 22, 2016 Don't get too carried away with your positive vs negative pressure balance. A slight positive pressure balance can help move stagnant air in odd corners or other places that are somehow out of the main flow, but that's about it. Any silly videos you have seen about it preventing dust or revolutionizing your cooling are nonsense. It doesn't matter how many fans are set-up as intake. When a dust particle gets close enough to an intake fan, it's coming in and most likely going to stop on the first charged surface it finds. Filters can help with that, but at the cost of restricting your low speed airflow. If you have a particularly dusty or pet-invested environment, that may be a good trade. Getting your case off the ground is often the most productive step, but not always possible. Even if it has to be an under the desk set-up, a small 3-4 inch boost may help keep the lower fans from really vacuuming the floor. The amount of air you can move passively out of the case is pitiful compared to an actual exhaust fan. Increased pressure does not mean increased exhaust. Doing PV=nRT calculations is going a bit far, but feel free to experiment with different fan combinations and compare. If you are worried about the balance, don't forget your radiator fans usually don't need to turn at high speed and move far less air than a normal free exhaust fan. You can run front intake, bottom intake, rear and top exhaust and still have a positive pressure balance. It's a more natural flow and hopefully will prevent a swirling mass of hot air in the center of your board trying to find a way out. Besides, who likes to run their fans maxed out? If you want positive balance, just increase your front intake speed by 100 rpm. You can always set the balance the way you want with fan control. Gone are the days when you have to plan this out ahead of time because all your fans run a constant voltage. I think the extra 120mm on top may be unnecessary. I don't have your case, but others have reported strange results when running the top fans in opposite directions. This is generally true any time you run adjacent fans in opposite directions. Link to comment Share on other sites More sharing options...
volvorwd Posted February 26, 2016 Share Posted February 26, 2016 i have a non airflow 750D with both front panels and the way i have my fans set up is two 120 bitfenix green led fans up front as intake and a 140 cooler master green led fan in the rear as exaust along with the two corasir 140 fans that came stock with my H110i GT as exaust up top, all on a custom fan curve thru my motherboards control software n corsair link.I plan on upgrading to diffrant fans in the front and rear To Corsair 140 Led Fans and 1 or 2 120 on the bottom. So Far so good with the system taht u can veiw in my pc specs below my username im in a room set at 72F This winter im seeing temps of: also i can confirm that ive only seen about 3 to 5 degree diffrance in overall temps of the system overall depding on the front panel i use. Link to comment Share on other sites More sharing options...
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