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Noctua D15S vs. Noctua C14S w/200mm top fan HAF XB

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New Member
Apr 16, 2018
As the title suggests i have a dilemma. I currently have and love a Noctua D15S single fan BUT.. I am considering getting a C14S for the following reasons.

My case is a HAF XB with 2 140mm intake and 1 120mm exhaust noctua low noise fans. I want to add a 200mm exhaust to the top to help with GPU temps but with the D15S there isn't room.
Currently i can place my hand over the top of the case (where a 200mm fan could fit) and feel warm air rising from above the GPU(duh).

My thinking is even though the C14S is a much smaller cooler than the D15, because of the design i could have the fan direction blow up towards the 200mm exhaust to keep with airflow but everything i've seen is that this is meant to be a blow down cooler which would fight the 200mm exhaust.
Unless i had the 200mm fan as intake? But coolermasters site shows the optimal airflow for that fan as exhaust so this just give me more questions than answers.

My current temps in games are around 38-40c for the CPU and mid 60s to low 70s for GPU. I know thats not bad but I have so much headroom on the CPU side i figure i could sacrifice a little to help the GPU.
I am using a Ryzen [email protected] stock volts and an ASUS rx580 3 fan running at the minimum 1722rpm on the GPU, i know i could just increase the fan rpm but my pc is virtually silent and i like to keep it that way.

To sum up, im wondering if switching to a C14s with a 200mm top exhaust would assist my GPU temps, but not impact my CPU temps to a point where im not happy with them either. Im trying to find that perfect balance.
If anyone has any input on how these coolers compare with the mentioned fan direction and airflow id appreciate it.
Youre really going to have to try man... :)

If it says to blow down, then certainly youll lose something nkt following their instructions.
If I'm reading this correctly you are saying your temps are fine, your rig is virtually silent, everything is stable, but you want to change this because you feel warm air rising out of the case? This is just my opinion, but you're overthinking. There are thousands of people out there that would love to have your condition. LOL

However to answer your question the C14S is not as good of a cooler as the D15S due to it's smaller size. As far as I can tell you can run it as a bottom up cooler but I would assume it wouldn't perform as well and certainly wouldn't be helping out the Ram/VRM's like it's designed to.

Personally I wouldn't change anything but I don't see any issue with trying it if you have the extra cash laying around. In a worst case scenario you put it back the way it was.
Somehow I doubt that this top 200mm will help much. CPU is not really heating up much. Graphics card some more but still single exhaust fan should be fine and a lot of hot air is going through all holes in the case.
If you have ~30°C in the case then additional fans won't change much. If you see high 30 then maybe add something on top. I just don't think it will change much even if temps are higher than you wish then are still safe.
Thanks for the reply. I know I don't necessarily have a cooling issue.
I just see my GPU temps hitting mid 70s and the GPU vrms hitting 95 and wanted an opinion since I have so much to give on the cpu side.
Its probably not worth changing like you all said, adding the 200 might just mess everything up more than it would help the gpu.
But if I do try it I'll be sure to post with a follow up.
The biggest and most effective way to help the GPU is to allow the fans to ramp up a bit when it starts warming up. Finesse that curve a little more to let her breath. Yes, this will create a little more noise but to an old Overclocker like myself, it's music to my ears knowing I'm putting her to work. Maybe it's just me but when I'm gaming and my fans all start ramping up it makes me feel like I'm gaming harder and the rig is struggling to keep up with me. Delusional I know but it makes me smile.
Okay soooooooo time for an update. I went ahead and bought the C14S and the 200mm top exhaust fan but also something else which i wish i would have just bought in the first place.

A PCI fan bracket for 2 120mm fans(noctua s12a) in my farthest from GPU PCI slot

Its the end of my weekend and i probably wont get to installing and testing the C14S and 200mm top fan until at least next week. I was able to do a before and after without and with the PCI fans and im actually shocked at how much of a difference it made.

My original issue was that i wanted to run my GPU fans all the way down so that my system would be virtually silent but i was having temperature "issues" when doing so. Not actual overheating issues, i was just overthinking.

I just did a 30 minute test using prime95 for the CPU, furmark stress test for the GPU, HWinfo64 for the temp monitoring. Its 74 fahrenheit in the room with ac. Heres the results

CPU is a Ryzen 1700 OC 3.7 at 1.188volts using a Noctua D15S single fan at 1200 rpm which is not max(1500 rpm).
GPU is an ASUS STRIX RX 580 at 1400mhz with the fan slider at its lowest 1722 rpm.


CPU MAX 64.5c

Thats 19c lower on the GPU and 36c lower on the GPU VRMS, im assuming its because the GPU fans rpm is not pushing enough air fast enough to properly cool but with the PCI fans it does

I dont expect adding the 200mm fan to make any difference to the GPU at this point but im still going to test the C14S and the 200mm exhaust to see the difference.

Will post another update when i get to that if anyone is interested.
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Well its time for the final update. Pictures included.

I would also like to add in both configurations the PC is virtually quiet until the GPU fan kicks in and i cannot hear it running when i stand on the other side of the room.

After 30 minutes of Prime95 smallftt and Furmark.
CPU fan speed is 1200rpm on both coolers.

Noctua D15S w/ PCI Fans
CPU MAX 64.5c

Noctua C14S(bottom mounted fan blowing up at exhaust) w/ PCI fans and 200mm top fan exhaust.
CPU MAX 66.8c

Whats interesting here is that I expected the CPU temps to go up slightly which they did, but I did not think the GPU temps would also go up slightly with the addition of a large exhaust directly above it.

So for anyone planning to use air cooling in a Cooler Master HAF XB Evo case, from my testing the best temperature to noise ratio is to stick with a massive tower cooler (i like Noctuas), skip the top 200mm exhaust and pick up a dual 120mm pci fan bracket with your favorite 120mm fans for your GPU.
This is the bracket i bought.

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Forgive me if I'm wrong here but that top 200mm fan looks to be an intake, not an exhaust. Do my eyes deceive me?
No they dont deceive you. I actually had it as intake by mistake when I took the picture and switched it around right after but didn't take another picture. The testing was done with it as an exhaust.