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View Full Version : Air Flow Ideas & Comments?


Samurai
11-13-04, 07:43 AM
Q1: Which is better, Front to back or bottom to top? I am just wondering which one of these you guys think works better. Atm i've got 2x80 inlet and 1x80 outlet, so it doesn't really support the whole negative pressure theory.

I would like to go 120mm fans but only i can't fit any at the back as a exhaust, only 1 as a inlet. So i'm thinking of cutting a blow hole putting in a Vantec 120 Stealth (53cfm, 28db) and then cutting a inlet at the bottom and putting the same fan in. Then i was thinking to get more cfm out than in i'll leave a 80mm pushing out the back.

What you think?

Q2: What about my psu as a exhuast? I'm still using some generic 300Watt psu in my case, but i've been looking at aftermarket ones which have multiple fans in them to move more air.

If i were to put a high CFM fan in my PSU back end instead of the generic fan now, would it be able to act as a exhaust fan? And if i were to add a second fan to the psu, would it be better to put it at the base of the psu just above the hsf or on the front side of the psu 90 degrees to where a blow hole would be?

Q3: What about other holes and openings? Some people claim that having extra openings in a case will interrupt the airflow or change the desired path. So would it be better if i seal my case totally and only leave the openings where i have my inlet and exhaust fans, or just leave all the little holes and stuff open?

Q4: As far as i understand it if i have 2 fans one on top the the other i will get more air pressure but the same cfm right? But if i have 2 fans side by side will i get more cfm but the same air pressure?

Q5: Fresh air ducts. I'm going to put in a fresh air duct (either 80mm or 92mm) so i can get that extra bit of cooling. The question is should i attach the end of the duct onto the actually cpu fan or end it just before. And also what materials have you guys built a fresh air duct out of before and if you do join it to the cpu fan how did you do it?

I know this post is fairly long with tons of questions, but i've just been thinking about air flow recently and these are all the questions i've got. So please any of you who have tried these types of mods or just have a opinion just let me know.

gokusimpson
11-13-04, 02:42 PM
Have more exhaust and intake. Negative pressure is better. The PSU can move some air. Ones with more fans move more air quicker out of the case. I have a million little holes in the top of my case, but it doesn't seem to have much effect on my cooling. My temps stay down. I've never tried 2 fans on top of each other so i dunno.

bluegreenshxt
11-13-04, 11:09 PM
Q1: Fans at the front bottom should be intake. Fans at the top back should be exhaust.

Q2: Not worth it, IMO, to mod a generic 300watt psu. Spend a few bucks and get a decent powersupply. Even an Enermax 350 is much better.

Q3: Holes at the bottom are the best. If you have a bunch of holes beside an exhaust fan, the fan will draw air through the holes and back out the case. It won't achieve a cooling effect. However, if the fan draws air all the way from holes at the bottom, it will drag the air through more components, giving them better cooling.

Q4: There would be more air pressure because you're pulling on the same amount of air with more fans, more force.

Q5: It depends how large the duct is. Someone here used a Pepsi can recently. If you're hole is big enough i suggest attaching it directly to the fan. Just don't cover the entire heatsink, only the fan, so the air can escape.

What makes you ask these questions? For most users/slight overclockers a fan at the back should be enough. As long as everything is running stable I wouldn't worry about temps too much.

Samurai
11-15-04, 01:08 PM
It gets quite hot here is SA in summer and i've just upgraded to a 3000+ Barton that is generating serious heat. I'm buying a Thermalright heatsink soon but my case temp went to 37C the other day and i need to being that down if my cpu temp is gonna get anywhere near low enough.

FragMonkey
01-22-05, 04:56 PM
Front to back. Gets all the air flowing around the case.

LazyAzN
01-22-05, 09:27 PM
Front to back, bottom to top, heat rises up, which is why I am replacing me 3 rear fans which are towards the top.

gokusimpson
01-22-05, 09:35 PM
Replacing them with what? I think your rig will be very loud like my current one is. Try to get stealth fans if you didn't already.

LazyAzN
01-22-05, 10:15 PM
Lol, I really don't care how loud it is... since my heatsink is like about 50 dba now, and makes it louder than all the fans combined... Im getting those sunon 50 cfm 40 dba fans... With a system exhaust.

z80
02-06-05, 10:09 PM
some advice ..place your hdd's in the airstream of the front fan is possible they will last
a lot longer running at 25c instead of 45 or something.

Zefram
02-07-05, 03:36 PM
some advice ..place your hdd's in the airstream of the front fan is possible they will last
a lot longer running at 25c instead of 45 or something.
Most newer casing, you can fit a 80mm or 120mm (mine) and it will blow at the HDD................
I recommended this for those running WD Raptor, it generates quite lot of heat........