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80mm case fan questions

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April 2, 2006 4:10:54 AM

I have a few questions about whether I should get an additional 80mm case fan for my computer. When the room gets warm (above mid 70s F), the computer gets a little hotter that I'd like (47-48 C) as it is always running under a high load. My case had a CPU duct, but I removed it as it wasn't in the right place for my board- it pointed somewhere between the far edge of the CPU HSF and the rear I/O ports.

The duct grille is perfectly drilled and spaced for an 80mm fan to be stuck there. I was going to stick one there but I recently built a unit that had 3 80mm case fans and each one of them was louder than my entire computer is. The only difference is that those fans aren't RPM-controlled by the motherboard and mine can be. Would those little fans spinning at 1500-1700rpm instead of the full 3450rpm make that much less noise? My 120mm and 80mm front fans makes little to no noise- I'd like to put another 120mm in there but the grille is not big enough for that.

So what do you think? Would it be noisy or not? Would it really help that much? Taking the side off of the machine lowers the temp about 1 C or so.
April 2, 2006 4:29:43 AM

Adding another fan would lower your temps and depending on which fan you get it can be quite too. It just has to be a low rpm fan.
April 2, 2006 4:34:18 AM

Quote:
Would those little fans spinning at 1500-1700rpm instead of the full 3450rpm make that much less noise?


A reasonable estimate is about 1dB per 100 RPMs for a single (quiet) 80mm fan. In some cases, the increase in SPL with fan speed can be even more.
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April 30, 2006 7:27:27 AM

U have 2 front fans? Unnessesary. Front fans are in principle worthless, unless that is they are blowing on the hdd.

Fans drawing air out of the case is the way to go.

Remove any sucking fans (unless they blow on the hdd which needs to be cool) and have a fan at the back instead.
April 30, 2006 2:39:53 PM

hmm, there is a CPU duct on the market tha twill attach on a 80mm CPU duct slot, it will widen and at the end u can place a 90mm or 92mm fan, that will help with ur noise problem and your cooling problem. i cant find it at the moment but ill look
April 30, 2006 2:41:54 PM

I had one intake fan in the front and one 120mm exhaust fan in the rear. I went ahead and put an 80mm intake fan in the side where the duct was and it is no louder now than it was before, and my computer runs a little cooler.

My computer never was noisy- I just didn't want it to become so.
April 30, 2006 3:15:37 PM

hey MU i gotta ask u 2 things

how is that Abit KN8 SLi?, any good?


2nd. try getting a speed controller on ur fan, it wouldnt cost too much. and if u really wanna be lazy, get 4 paper clips, get a 120mm fan and well, start bending. use papers clips to mod a 120 on the 80mm slot dont stick the 120mm to close to the case keep some space between the fan and the side panel. should work fine

i had a 92 fan tha ti pulled out of my case i couldnt ge tit back in the screws were short far and the thread were really far apart. i got pissed. used 3 paper clips it hots the fan as well if not better than screws :) 
April 30, 2006 3:17:22 PM

Quote:
Front fans are in principle worthless, unless that is they are blowing on the hdd.


Bartender, I'll have whatever he's having!!!
Pulling cold air in through the front, what a BAD idea.
Shmoe.
April 30, 2006 4:23:25 PM

The KN8-SLi is a very good board. It's well laid-out with the possible exception of the FDD cable being at the very front bottom edge of the board and a little hard to get at. The passive chipset cooling works very well and means no little 5000rpm fan on the chipset to make noise and die on you after 6 months.

The board is very stable and has been running constantly with two Folding @ Home cores going 24/7 for weeks at a time with no hiccups. About the only issue I had with the board is the default Ethernet NIC drivers in my distribution (called "forcedeth") cause erratic NIC behavior when the unit is left on for more than a day or so. The official NVIDIA "nvnet" drivers do the trick. I can't comment about Windows drivers stability nor SLi or RAID performance. It runs my two independent SATA drives (one's an SATA-300, the Raptor a -150) just fine though. I'd recommend this board wholeheartedly.

The BIOS has a function that allows for a fan speed percentage (40, 50, on up to 100%) control. It comes set at 60% and I upped it to 70% and that is a good compromise between cooling (40-42 C under full load) and noise (pretty quiet.)
April 30, 2006 4:30:09 PM

cool thanks, i cant find 1 review on the net about the KN8, well i did find one its in german which doesnt help since i speak english.

that really helps
'
thanks
April 30, 2006 4:46:00 PM

Great MB, I have 1. OC's very well especially for the $$.
April 30, 2006 5:04:28 PM

how high of an OC cna u get it?

MU did u try the paper clip technique?

test it fist take the front 120mm fan off and paper clip it to the side panel


what case do u have?
April 30, 2006 8:35:35 PM

I want the frequency scaling (Cool 'n Quiet) to work, so I don't OC any. I got an 80mm fan for a few bucks and put it on the side and it works fine. I did that a few weeks ago.
April 30, 2006 9:04:59 PM

ok, cool, so u highly recommend the KN8 SLi?
April 30, 2006 9:07:10 PM

Yes, I do. It's worked well for me.
April 30, 2006 9:25:50 PM

what about the passive cooling?

u kno what PM me a messenger addy
May 1, 2006 5:44:36 AM

Quote:
Front fans are in principle worthless, unless that is they are blowing on the hdd.


Bartender, I'll have whatever he's having!!!
Pulling cold air in through the front, what a BAD idea.
Shmoe.


Yes is a bad idea. Think about it. Have you ever seen a laptop computer for example with a sucking fan?
Does the X-box have a fan blowing in or out?
How is the ATX original specification? Does it have the PSU fan blowing into the box?
May 1, 2006 10:49:35 AM

I have thought about it, and I soundly reject your claim. Laptops get hot. Xboxes overheated initially. Let's agree to disagree. You can keep recycling the same hot air all you want. I'll sit back, with my cool computer.
May 2, 2006 9:50:04 AM

Quote:
I have thought about it, and I soundly reject your claim. Laptops get hot. Xboxes overheated initially. Let's agree to disagree. You can keep recycling the same hot air all you want. I'll sit back, with my cool computer.


Front intake fans are only good for cold air on the HDD. Otherwise you be better of having the same fan at the back blowing out.
But I guess the engineers making all the laptops on the market, as well as the people behind xbox etc. are all wrong. You are the guru. I will at once move my fans to the front sucking in the air. :lol: 
May 2, 2006 11:45:46 AM

It would also depend on the fan you get. If you look on Zipzoomfly they have quite a few that would fit the budget. Now stay away from deltas; they are the standard and one of the loudest fans you can get.

This paticular fan does a great job for me and is reasonably quiet with great air flow: Coolermaster TBF-B12-E1 Tri-Blade System Fan . Now you are paying more for the fan, but as in all things you get what you pay for. I'm tempted to trade out my AMD stock fan for this one to see how it does on cooling......
May 2, 2006 12:14:50 PM

That is actually the rear fan that came with my case. It is pretty quiet. I think the AMD heatsink fan is a 72mm IIRC.
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