Building a silent machine

[bariumsulfate]

Hey guys. I came across this site today and thought I would consult all the expertise here. I built my first machine during the summer of 2009, and it works very well. However, I am not completely satisfied with its acoustics. Now that I have some extra cash, I want to work on silencing my computer. Here are descriptions of some of the components I am using:

VIDEO CARD - GeForce 9600GT - Don't know how loud it is.
POWER SUPPLY - 650W, no fan. Runs much cooler than the unit it replaced.
EXHAUST FAN 1 (19dBA, 90CFM) - Doubt it's 19dBA, it sounds louder.
EXHAUST FAN 2 (19dBA, 23CFM) - Side fan, also probably a little louder.
INTAKE FAN (20dBA, 44CFM) - Quiet enough I guess, still audible up close.
CPU FAN (25dBA, 79CFM) - Can definitely hear it up close.

When I open the side of my case I actually hear less noise. With the case closed, due to the acoustics of the case I hear a deeper whir, while if it's open I guess it's technically louder but I don't notice it at a distance because it's a higher pitch. If that makes sense. So I think the case is also partially to blame for the noise.

Since temperatures are a concern, here are some of mine at steady state (C):
MOTHERBOARD - 36
CPU - 35
GPU - 45
ICH - 73 (I called Intel multiple times. Every time they said it's normal for my model DP43TF, and that the board is designed to handle up to like 100C or something. So I am convinced that 70s is OK. When I first built my machine with an old power supply this temperature would hit 85C.)

I manually control fan speed (800RPM for inlet and side fan, 1200RPM for exhaust fan). Temperatures don't change appreciably at higher speeds. I don't game that often, and when I do I don't care that much about noise so I'll make sure to turn up the fan speeds.

Don't get me wrong; the computer is already pretty quiet by most standards. Most of my friends who've built PCs have much louder machines. But I'm really particular about background noise, and I really want to get something really quiet.

For example, you know those Dell computers you find at libraries? I am talking that kind of noise level. Most of the time I just do work, listen to music, and browse the Internet.

Anyway, I was wondering if anyone had any advice on how I can work on this problem. Since temperatures are not much of a problem for me, I am considering switching to quieter fans. For example:
http://www.endpcnoise.com/cgi-bin/e/std/sku=120mm_silenx_11db.html

I might also try to replace the CPU cooler. However, I am concerned that I'll mess up my processor during handling, due to sticky old grease or something. Has anyone had any experience swapping a CPU cooler?

The other thing I am considering is getting a case advertised specifically as having low noise. (www.endpcnoise.com) One of the cases they advertise is the Antec Sonata III, which can be found cheaper at newegg.

Sorry for the long post. I am open to any suggestions and would really appreciate your input.

[bariumsulfate]

I decided to disconnect all of my case fans and check the noise level. I think that replacing my current fans with quieter SilenX fans would help a lot, so I will DEFINITELY invest in those. However, there is still a bit too much noise for my taste from either the CPU cooler or the graphics card, or both. I could not reliably isolate one from the other, as I have no way of safely disconnecting them.

So, in the near future I may have to replace my CPU fan, and get a quieter fan for my graphics card. Is the latter commonly done, or has anybody here had experience with it? I just want to get a feel for how risky a procedure it is. Also, any suggestions for a good, silent heat sink for a socket 775?

Also, I forgot to mention that my machine is VERY loud during boot. I believe the GPU fan goes full speed, and it produces a somewhat high-pitched whir. Not that I care about noise during boot, but maybe this would imply that my GPU fan is naturally a major source of noise?

[RickyTick]

I would guess to say that the gpu fan is making most of the noise. You could change the gpu to a dual slot card. They tend to be a little quieter. There are also fanless video cards, but they tend to be lower performing cards too.

I'm curious on your choice of manual fan speeds, 800 for inlet and 1200 for outlet. I would have made them just the opposite.

[bariumsulfate]

Thank you RickyTick for your input. I will consider dual slot cards, but I wonder if there are more cost-effective ways of silencing my video card, like replacing the fan. I will probably look into it on Tuesday when I have more time. Anyone have any experience with it?

My choice for fan speeds was sort of arbitrary. Any reason why the opposite would be better? I will try it.

Speaking of fans, here is an interesting find:

http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=5267687&csid=ITD&body=MAIN#detailspecs

It is basically water cooling for the CPU. Now if you watch the video until the end, the guys at Corsair say that it's actually better to have the fan blowing cold air into the case from the back, rather than have it exhaust. I can see how that would work, since the radiator is going to be cool, and this way the inside would get an intake of cooled air. But I must admit it sounds like a weird setup. If I'm right most people intake from the front and exhaust out the back, don't they? The front of my case has grills that make it less ideal for exhausting, so I don't know how well this setup would work for my case.

[The Wise Monkey]

Hi barium.

I changed the stock fan on my 4850 to this Zalman cooler: http://www.newegg.com/Product/Product.aspx?Item=N82E16835118037&cm_re=zalmna-_-35-118-037-_-Product

It offers very good cooling, so you can probably turn the fan speed down a bit. It is quite expensive though.

[RickyTick]

My choice for fan speeds was sort of arbitrary. Any reason why the opposite would be better? I will try it.


If your fans intake less cfm's of air than are being exhausted, then you create negative air pressure, or sort of a vacuum. In this case, the fans will be pulling in air from any place possible, such as; drive bays, USB ports, I/O shield, firewire ports, etc. This could cause an excessive amount of dust and dirt to get in you system.

So if you have positive air flow (intake more cfm's than exhausted), then excess air will get forced out of those previously mentioned ports. End result should be less dust.

Make sense? Sometimes I don't explain things well. :)

[bariumsulfate]

Ah yes, that does make sense. I have taken your advice and have been running my intake faster than exhaust for a few days.

[RicheousWeasel]

I am fairly certain that higher exhaust fans, while creating noise from the afforementioned "sucking" of air from any possible place, make the machine run cooler than a positive air flow. Dust will get in regardless because the air will come in anyways, so to cut down on that, make sure your wires are tucked out of the way of the airflow to allow for less obstruction and increase fan efficiency. Higher air pressure creates heat, low pressure creates less heat. Negative air flow is a cooler setup. If you really want a quieter fan setup, get larger fans. They move more air with lower speeds and hence, are quieter. Also, fans with more blades are quieter because the blades themselves vibrate through the air. More blades means a different pitch to the vibration, and less noise.

I hope this helps. I know this is an older thread, but newer viewers might benefit.