Airflow in NZXT S340

Distracted · 15 Oct 2018 at 00:21

Np. I'm glad it has made a difference.

To help with the gpu you can swap the top fan to the front until you buy another one. That will blow cool air towards the gpu and having more pressure in the case will force the hot air out, rather than trying to suck air in through the various case holes and cracks. One exhaust fan and 2 intakes should show better temps.

mikedigitales · 15 Oct 2018 at 09:14

You could stick the rad in the roof, 120mm exhaust on the back, two intakes on the front (140mm if possible). That should help with the graphics card temps, and good graphics card temps mean higher boost, so higher frame rates. For gaming, graphics card temps are probably more important then CPU being a few degrees cooler?

elrasho · 15 Oct 2018 at 09:19

Distracted said:
Np. I'm glad it has made a difference.

To help with the gpu you can swap the top fan to the front until you buy another one. That will blow cool air towards the gpu and having more pressure in the case will force the hot air out, rather than trying to suck air in through the various case holes and cracks. One exhaust fan and 2 intakes should show better temps.

I dont think I can fit another fan at the front, if you look at the picture in post 4 you can see the H45 is taking up some of the space for the bottom slot.

mikedigitales said:
You could stick the rad in the roof, 120mm exhaust on the back, two intakes on the front (140mm if possible). That should help with the graphics card temps, and good graphics card temps mean higher boost, so higher frame rates. For gaming, graphics card temps are probably more important then CPU being a few degrees cooler?

Rad wont fit on the roof due to case restrictions, also my card hits it maximum boost without me OC'ing it (which I dont need to day for my games)

elrasho · 15 Oct 2018 at 09:51

Had a thought, my soundcard is sitting in a PCI slot right next to the 1080Ti fans. I'm thinking I could move it down to the other PCIE slot, but will this make my 1080Ti run at 8X rather than 16X? Plan is to move the sound card from the red rectangle to the orange rectangle.

EDIT: found the answer in the manual which is actualyl quite good. My GPU should still run at 16X if I use PCIE2 for the sound card.

elrasho · 15 Oct 2018 at 12:33

Been doing some digging around the net and found this screenshot:

This person has mounted a second fan on the front of the radiator thus taking up less space on the case, so he's managed to get another fan underneath. I'm going to give this a try by taking my fan off the H45 and putting it at the front and still sucking in cold air. That should give me room to put another fan underneath for the 1080ti.

doyll · 15 Oct 2018 at 14:46

elrasho said:
So I took the front cover off my case and temps have gone down by 10C across the board. I think this case has a design flaw, I'm gonna get another 120mm fan and have it blowing hot air out towards the front:

(how do I resize pics?)

Let's stop and think about the above image. Assuming radiator is intake we have a radiator with a fan pulling air through it into the case and a big hole below the radiator with no resistance to airflow. When front cover is removed the resistance is the same for opening below radiator as in front of it so cool room air flows into radiator. But when front is installed the resistance created by filter and grill of case front is much greater than the resistance of the hole in radiator mounting panel so it's much easier for air to be drawn from inside of case back in front of radiator than it is to draw air though the grill and filter when front is mounted to case .. and each time the air circles around through hole and back through radiator the hotter that air gets inside of case and the hotter the components both on air cooled components and on radiator will be.
Block all openings in radiator mounting panel not covered by radiator and I'm betting your temps will be much better.

elrasho · 15 Oct 2018 at 15:01

doyll said:
Let's stop and think about the above image. Assuming radiator is intake we have a radiator with a fan pulling air through it into the case and a big hole below the radiator with no resistance to airflow. When front cover is removed the resistance is the same for opening below radiator as in front of it so cool room air flows into radiator. But when front is installed the resistance created by filter and grill of case front is much greater than the resistance of the hole in radiator mounting panel so it's much easier for air to be drawn from inside of case back in front of radiator than it is to draw air though the grill and filter when front is mounted to case .. and each time the air circles around through hole and back through radiator the hotter that air gets inside of case and the hotter the components both on air cooled components and on radiator will be.
Block all openings in radiator mounting panel not covered by radiator and I'm betting your temps will be much better.

Thanks but that's not how I have it setup, see my posts after on how I have it setup. My next adkustmenr is to add another fan on the H45 and attach it to the case on the same place (currently looking for long emijg screws). Also add another intake fan under it for the GPU.

doyll · 15 Oct 2018 at 15:17

elrasho said:
Thanks but that's not how I have it setup, see my posts after on how I have it setup. My next adkustmenr is to add another fan on the H45 and attach it to the case on the same place (currently looking for long emijg screws). Also add another intake fan under it for the GPU.

If that isn't how you had it setup, why did you post the image?

Regardless of how you have radiator setup and/or fans setup, if there are openings in the mounting plate that are not blocked they will leak heated air from inside of case back into the space between front and mounting panel meaning you are not getting air into radiator that is being pre-heated by the heated air leaking back into that front area. So even with a fan below rad I would block off any openings not covered by fan and rad.

elrasho · 15 Oct 2018 at 15:38

doyll said:
If that isn't how you had it setup, why did you post the image?

Regardless of how you have radiator setup and/or fans setup, if there are openings in the mounting plate that are not blocked they will leak heated air from inside of case back into the space between front and mounting panel meaning you are not getting air into radiator that is being pre-heated by the heated air leaking back into that front area. So even with a fan below rad I would block off any openings not covered by fan and rad.

You missed the context of that post, you need to read the posts and not just look at the pics. As it stands now all I've done since OP is set rear fan to exhaust and flipped the H45 fan so it now pulls cold air in from the front through the radiator.

doyll · 15 Oct 2018 at 16:08

elrasho said:
You missed the context of that post, you need to read the posts and not just look at the pics. As it stands now all I've done since OP is set rear fan to exhaust and flipped the H45 fan so it now pulls cold air in from the front through the radiator.

Seems you are more guilty of not reading and understanding my posts than I am of yours.

You said

"So I took the front cover off my case and temps have gone down by 10C across the board. I think this case has a design flaw,"

It's not design flaw. It's user error by leaving openings in mounting panel for possible use by other fans or larger rads. If case was not designed with these openings we couldn't mount needed fans and have needed airflow. The reason your temps were so high before was because these openings were letting the air being pushed into case and mixing with heated air inside of case to leak back in front of fan/s and back into case and around and around getting hotter and hotter.

You have added a fan below rad, but as I said before if there are any holes still not blocked off, heated air will still be leaking back into front of case .. just as I explained in my 1st post above.

elrasho · 15 Oct 2018 at 16:14

doyll said:
Seems you are more guilty of not reading and understanding my posts than I am of yours.
You said

"So I took the front cover off my case and temps have gone down by 10C across the board. I think this case has a design flaw,"

It's not design flaw. It's user error by leaving openings in mounting panel for possible use by other fans or larger rads. If case was not designed with these openings we couldn't mount needed fans and have needed airflow. The reason your temps were so high before was because these openings were letting the air being pushed into case and mixing with heated air inside of case to leak back in front of fan/s and back into case and around and around getting hotter and hotter.

You have added a fan below rad, but as I said before if there are any holes still not blocked off, heated air will still be leaking back into front of case .. just as I explained in my 1st post above.

My point is I never left the front cover open as my normal method, you seem to think I did. I only did it to see how it would affect temps and they went down a lot only because I had the H45 fan blowing out the front. Because of the case design this hot air was bashing into the cover, but by flipping the fan and putting the cover back on my temps are much better now. BTW I havent added the fan below the rad... yet.

doyll · 15 Oct 2018 at 17:04

elrasho said:
My point is I never left the front cover open as my normal method, you seem to think I did. I only did it to see how it would affect temps and they went down a lot only because I had the H45 fan blowing out the front. Because of the case design this hot air was bashing into the cover, but by flipping the fan and putting the cover back on my temps are much better now. BTW I havent added the fan below the rad... yet.

No, you seem to think I did.

All I did was use your image as an example. My example even talks about how the cover filter and grill effects the airflow through any holes not blocked in fan/rad mounting panel.

It wouldn't matter if rad was pushing out or pulling in, if there are other openings in mounting panel and front is on the case the heated air will move back through them. The problem is not 'case design this hot air was bashing into the cover'. The problem is pressure differential between inside of case and area in front of mounting panel when front cover is installed having openings not blocked off .. just as I keep telling you and you refuse to listen to because you would rather argue about what you said. The temps are not improved 'by flipping the fan and putting the cover back' but because you installed a 120mm fan in the big hole that was letting air circle back to radiator fan.

I'm willing to try explaining it more if you do not understand how the air is circling, but I will not reply if you continue trying to make a point about anything else.

elrasho · 15 Oct 2018 at 17:07

Nah I get it mate

, BTW I haven't installed a fan in that big hole at the front hole, it's still empty but I have the front cover back on just to clarify

doyll · 15 Oct 2018 at 17:35

Then either block off the openings or put a fan in the big one moving air same direction rad fan is moving air. Below is link to how airflow works and how to optimize it.
https://forums.overclockers.co.uk/t...-i-put-my-temp-sensor.18564223/#post-26159770

I would use front with just intake fans to bring cool air into case. Use something like PH-F140MP or PH-F120MP so they have high enough pressure rating to overcome grill and filter resistance. I would mount rad as rear or top exhaust. 2x front intake fans with one supplying cool filtered airflow to rad and other supply cool filtered airflow to GPU cooler.

This way all it's heated air will be more likely to be dumping outside of case and not warming up the cool air coming into case and to them.

elrasho · 15 Oct 2018 at 17:45

Yep I plan to put another fan in the big hole but need to make room for it as the rad is overlapping into its space (pic in a post above).

To overcome this I plan to mount the H45 fan on the otherside of the rad so that's the fan is mounted onto the case (like in post 25). This should give me room to fit a 120mm under it.

Can't mount the rad anywhere else, bits of the mobo/case get in the way.

doyll · 15 Oct 2018 at 18:07

I don't know if that will work. Fan need about 45mm clearance between front of fan and front cover so it can draw air into the fan. Even that is restricting airflow to fan if not on all side to front of fan. Is there 70+mm of clearance between fan mounting panel and inside of front cover?

elrasho · 15 Oct 2018 at 19:24

doyll said:
I don't know if that will work. Fan need about 45mm clearance between front of fan and front cover so it can draw air into the fan. Even that is restricting airflow to fan if not on all side to front of fan. Is there 70+mm of clearance between fan mounting panel and inside of front cover?

The gap is more like 50mm.

I found a 120mm spacer frame in the H45 box so tried to mount that in front of the rad like I said, but the white bar of the case gets in the way lol

Theres literally nowhere else to put the rad so I cant put another fan under it. The only thing I could try is get one of those PCIE slot fans from the old days to blow hot air from the GPU outside the back of the case :eek:

Also I don't like how the H45 pipes are pressing on the copper bits of my 1080ti. It causes it to sag ever so slightly. I tried rotating the rad by 180 but then it won't fit on the front slot because of the crap at the top of my case

elrasho · 15 Oct 2018 at 20:15

After an hours a gaming CPU temp maxed at 54C and GPU 61C.

I'm happy with that :cool: