Once Again...Is it a good CFM rate? Is it noisy ?

[CamisaAmarela]

Guys:

I'm building (slowly, unfortunatelly) my little system => XP1800 (not OCed now; maybe in
a few months ) + PAL8045 + SOYO DragonPlus + (Gainward, ASUS or Leadtek) GeForce3 Ti200
(OCed for sure !!!) + 2x256Mb DDR (Crucial or Kingston) + a 400W PSU with 2 fans (intake/exaust).

I got two doubts about cooling and noise. I'm planning to use these things for cooling:
2xPAPST 8412NG (40.6CFM;32dbA) intake with aluminum mesh filter (lower front);
1xPAPST 8412NGH (46.5CFM;37dbA) exaust (back - over PSU);
1xPAPST 8412NGH (46.5CFM;37dbA) sucking my PAL8045.

All of them are 80x80mm. The case came with these 3 fan holes and I already cut the case fan grates.

So I'll have 72CFM intake(10% loss because the fiter) and 46.5CFM exaust. Is it good ?

So I'll have 35dbA intake, 37dbA exaust + 37dbA internally...aproximatelly 39.5dbA total[/b].
Is that too noisy?

OR, if I change the intake fans for PAPST 8412NGM(34.1CFM;26dbA) and the exaust/HSF fans for
PAPST 8412NG (40.6CFM;32dbA), I'll have 61CFM intake, 40.6CFM exaust with +/- 33.5dbA. Still
it good?

Thanks in advance .

 

[Kipper]

Bad idea in terms of air flow. You've got more intake than exhaust, meaning that there will be more air sitting toward the front of the machine while the back fan tries desperately to suck out air. This will cause more heat buildup than you need, and your front fan will not perform as well because the excess air will either A.) not go in or B.) be pushed out the sides of the case. You generally want equal intake and exhaust, perhaps more of the latter so that you have a clear airflow through the case from the front to the back.

 

[KouklatheCat]

I agree with Madcow. I would consider stepping up the exhaust cfm. And if you have a cat I would make sure you put a fan grille on any fan he/she can get near. My cat is just dumb enough to try and play with a fan blade moving at 5400 rpms.

 

[Demon-Xanth]

Unless you have a sealed case, a bit more intake would be a good thing because of air seeping out of cracks. You might consider stepping upto about 60CFM exhaust.

In my last case, there were perforations on the side that I used in leiu of extra exhaust fans and it yeilded a flow that went from the bottom front left side of the case to the top back right (kinda hard to describe) and kept my case near room temp.

 

[mboy]

Don't forget to include the CFM of the PSU exhaust fan. I would say you will probably be ok. You will have slightly more intake volume then exhaust and that is fine.

 

[Egrimm]

It won't be noisy, but it'll be hearable, let me put it that way. I have three Papst 8412NGH fans in my case (intake, exhaust and on PAL8045) and it's not silent but doesn't irritate me nearly as much as the 7000rom fan on my old DragonOrb3.

 

[ShinSa]

<< Unless you have a sealed case, a bit more intake would be a good thing because of air seeping out of cracks. You might consider stepping upto about 60CFM exhaust.

In my last case, there were perforations on the side that I used in leiu of extra exhaust fans and it yeilded a flow that went from the bottom front left side of the case to the top back right (kinda hard to describe) and kept my case near room temp. >>




You'd want your cool air to cool most part of your system, that is to flow in from the bottom, pass through the middle where the cpu lies and exit towards the back up top. Air seeping through cracks won't be as effective.

AMD even states that having an intake fan can just build up warm air.

read #8

 

[CamisaAmarela]

Beside the case "cracks", side and rear panels of my case have those ventilation cuts (like small fan grates). The PSU
manual don´t mention anything about the CFM performance of its fans - so I didn´t considered them in the CFM estimated
results. Because I don´t want to cut a new hole in my case (I´d rather keep the originals), change the PSU fans could be an option. The problem is that if I open the PSU, I´ll lost the warranty. What do you think ?

Tks...