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Case Air flow advise.

Posted: Thu Jan 23, 2003 8:53 am
by mynci
I would very much like peoples advice before i go ahead and start hacking up my case and shelling out my hard earned.

I currently have a 'nothing special' aluminium tower case. its air flow is apauling. I currently only have a dual fan psu sucking the air out (and hence in through the front) of the machine.

I think i need to get about 6 fans, i ideally want to get some of the Noiseblocker UltraSilentFan S2 as they come with all the pots and knobs and are nice and quiet (also they would look cool as the front fans are visible). however if i cant source them then the Papst 3412N/2GL is my other option. (i am open to suggestions though). I would like to mount all the pots on the front plate of one of the drive bays so i can easily change speeds. i was planning on running the fans at around the 7v mark.

The following is a quick picture of the case half as i plan to make it.

Image

I am planning on:

replacing the current zalman fan with one of the fans.

putting one of the fans above the graphics card as shown, (removing the current fan)

Putting one of the fans on the exhaust port under the psu on the back.

Replacing the fan at the back of the psu with one of the fans and then removing the one sucking upwards altogether.

Putting the remaining two side by side on the front of the case, pulling air in. this neeeds me to actually alter the case though.

my thinking was that by mounting the barracudas sideways on some foam they will get a good airflow over them and keep quiet.

Do you think this will be a suitable airflow? will the modified psu survive with the lower fan? whats you advice on the fans? any improvements you can think of, in fan positions etc? will the small hole in the base cause a problem? will it be nice and quite?

The machine is a p4 2.4GHz, 512MB ddr 333, 550w qtec gold (quite cheap) psu. 2 80gig seagate baracudas, floppy, cdrw, dvd drive, geforce 4 ti4200 (made my PNY).

many, many thanks
Mynci.

Posted: Thu Jan 23, 2003 6:26 pm
by wonsungi
I'm not sure you need all those fans~ when you talk about "6 fans," I can only think about what a racket they will all make, even if they are quiet models.

I used to have 3 Panaflo L1's-- 120, 90mm intake; 90mm exhaust. I tried unplugging them all, and my system still runs fine; much quieter, although slightly warmer. The Panaflo's are known for being fairly quiet, but it's still much more preferable with them off.

Is there some reason you feel the need to add fans? Is your system unstable right now? If it ain't broke, don't fix it!

If you must add fans, I'd try adding one fan at a time. Either the exhaust port or front lower intake seem to be good places to start.

Remember, using larger fans that spin slower create less noise for the same amount of airflow as smaller, faster fans. I prefer to use 90 or 120mm fans, but that usually requires modifying the case. And grommets seem to reduce fan noise, too.

Posted: Fri Jan 24, 2003 1:09 am
by Gandalf
Can you say deafening? Then again, I have 5 fans and my pc is dead-silent :D.

Posted: Fri Jan 24, 2003 1:10 am
by mynci
sorry, at the moment my sytem is very loud, it only has a dual fan psu doing the sucking (ie fan at the bottom of the psu and one on the back, bth pushing air out of the machine). so currently there is only a small intake vent on the front of the machine (no fans).
the graphics card currently has its stock hsf and the zalman fan on the psu seems too loud (once i sort the other fans).
If you think it would be enough just to remove one af the fans from the psu and replace the other, then that would obviously be better, however i didn't thing that would be enough airflow.
my case currently has a dotted grid effect on the front of at the base and a standard fan mounting port on the rear of it. i could put, say, two exhaust fans (one on psu and one just underneath) and nothing or one fan on the front (and not modify my case) however i was thinking that would create a negative air pressure inside the case.
Please do let me know what the best solution is, i am quite inexperienced at this and i just want a pc as quiet as possible for as little money.
if its a viable option the my cheapest solution would be to replace one fan in the psu, the zalman fan with a quieter one and put one over the grapics card. i would still move the hard disks to the bottom of the case and ut them on some foam to decouple them as they run very hot and i would like to eliminate that very tiny last bit of noise as best i can.
i hope this makes sense now.

cheers

Gandalf - you think that setup will be very loud? even with the fans running slowly? can you explain why (not because i think you wrong, just because id like to understand it)

Posted: Fri Jan 24, 2003 1:21 am
by mynci
also, i just thought i can easily put 120mm fans over the cpu and graphics card. any idvice on which model.

Posted: Fri Jan 24, 2003 2:25 am
by Gandalf
I suggest you simply add an additional exhaust fan to the system and install a front intake fan. You also might want to consider replacing the stock hsf's with silent models, or even fanless models on the chipset/GPU.

- Bram

Posted: Fri Jan 24, 2003 2:43 am
by mynci
ok so perhaps if i put one 92mm fan on the front. replace the 80mm fan in the back of the psu and put an additional one on the exhaust. then replace put a 120mm fan over the gpu (with stock hs) and a 120mm over the zalman flower. will that be quiet. and enough airflow?
cheers.

Posted: Fri Jan 24, 2003 8:40 am
by Gekkani
Gandalf wrote:Can you say deafening? Then again, I have 5 fans and my pc is dead-silent :D.

How can u got a dead silent PC with 5 fans ??

I'd like to know your setup... ^^

Tell me please.

Posted: Fri Jan 24, 2003 11:48 am
by powergyoza
Gekkani wrote:
Gandalf wrote:Can you say deafening? Then again, I have 5 fans and my pc is dead-silent :D.

How can u got a dead silent PC with 5 fans ??

I'd like to know your setup... ^^

Tell me please.
Yeah, I second that. Are you running your fans below 5V? IMO, that could be the only way to do it. Remember, I've got 5 Panaflos too all at 5-6V and it still makes a wee-bit of noise (it's not annoying mind you).

Posted: Fri Jan 24, 2003 11:54 am
by Gandalf
1) All fans are PAPST's, most at 7v except for my cpu fan which is at 5v.
2) Aluminium (lian li) case with paxmate (I decided to get the paxmate after all, and yes it does block pretty much all remaining fan noise)
3) Zalman PSU (free of charge .. can't beat that price!)

The only noise my pc produces (aside from harddisk and cdrom noise) is the noise of the air flowing through my front filter. I can't hear the fans spin or anything, I can just hear the air whizz a bit, and it's not annoying at all. When I move back from my PC about a metre I can't even hear it at all.

I'm still experimenting with my harddisk, it's one of thoise noisy Maxtor beasts. I don't really fancy it, but it *is* fast.

Oh a little side note, all my fans (and grills) are attached with the Lian-Li fan attachment thingies :P. They look a lot like those blue fan isolators, though they're a bit different.
When I remove my front filter there's even less noise, but I don't fancy dust all that much.

Posted: Fri Jan 24, 2003 4:48 pm
by mynci
what filter is it gandalf, does it work? i hate having to clean the dust from my machine on such a regular basis. how much extra noise and reduced airflow does it cause?


how much airflow do you think is needed through my case in total? how many fans will be sufficient?

cheers

Posted: Sat Jan 25, 2003 4:21 am
by Gandalf
It's the standard filter that came with the Lian Li case. It's nothing fancy, but I have noticed that it does stop quite a lot of dust from entering the case!
It causes the air to "break" though, which makes it slightly more audible. Don't think it reduces the airflow too much.

Posted: Thu Jan 30, 2003 6:49 pm
by marioncyclonefan
Does anybody here use a blowhole on the top of the case? Or has that fallen out of favor? I currently have a Sunon 120x25mm 69 CFM blowing out of the top - seems to cool the case temp quite a bit. It's fairly quiet but still too noisy for me. I did have a YS Tech 120x38mm 121 CFM mounted in the side. It did a tremendous job of cooling the case and the cpu but sounded like airplane taking off.

Posted: Thu Jan 30, 2003 8:04 pm
by powergyoza
Unless you want to completely redesign your internal airflow, blowholes are not a good idea. If it's in the normal location (in front of the PSU) it wil steal precious cool air away from the HSF's.

Posted: Thu Jan 30, 2003 9:08 pm
by marioncyclonefan
Speaking of the psu - why is it open to the inside of the case at all? Seems like the best solution for cooling the psu would be to draw air from outside the case and then out in another direction (up?). Then have the case airflow draw outside air and have it flow out the back over the cpu.

Posted: Thu Jan 30, 2003 11:02 pm
by powergyoza
marioncyclonefan wrote:Speaking of the psu - why is it open to the inside of the case at all? Seems like the best solution for cooling the psu would be to draw air from outside the case and then out in another direction (up?). Then have the case airflow draw outside air and have it flow out the back over the cpu.
My point exactly! That's in fact what I did here: http://forums.silentpcreview.com//viewtopic.php?t=2842.

In theory, if we take the PSU out of the case airflow equation, all the components below it - the CPU, the regulators, etc will experience cooler temperatures. Y? B/C the PSU won't be stealing air from them anymore.

Posted: Fri Jan 31, 2003 9:47 pm
by blinky
today i moved the fans around in my case and managed to get a better airflow with fewer fans! i've got a lian-li PC60 and had previously had the four fans that come with it (2 front intake, 1 rear exhaust, 1 top exhaust) all at 5v, papst 80mm and 92mm at 7v in the psu (enermax), and one of those 12db (yeah right!) papst 80mm over the cpu (Athlon XP 1600+ with SK6 h/s).

today i decided to go for a switch about, went to 1 front intake, 1 rear intake and 1 top exhaust all at 5v, then took out both papst's in the psu and put the spare front intake fan in the 80mm hole as an exhaust at 5v, cpu fan stayed the same. now the rear intake brings cool air directly to the cpu fan, and the hot air from that rises up to the psu and blowhole where it's exhausted.

temps have dropped from 42C case, 58C cpu to 35C case and 52C cpu (standard MBM readings, Prime95 running). just shows that less fans with a better designed airflow can make a big difference! noisiest thing is now the cpu fan, but with reduced temps maybe i can slow that down too