Help with noise and thermal problems with a new PC

February 22, 2004 1:33 PM

I just built a new PC. Having noise/thermal problems, need advice thanks! {more inside} of course

This PC is crammed with stuff, 3 hard drives, 2 CD drives, etc in a large case. When it was fully built, it had a total of 7 fans - 2 built-in to the power supply, one on the CPU, one built-in to the video card, one blowing over the three hard drives (critical), and two extra ones, in the front and back of the case. It worked great, system and CPU temps were around 40 C, but it was one noisy mother. It had a continous, loud hum that drove me nuts. So I disconnected the two extra case fans today. Temps have gone up a few degrees but all I've been doing so far is reading websites. Does anyone know or have any experience with this? How many fans do I really need? Are the case fans necessary? Are there any fans that are actually very quiet (not just the advertising hype)? I just got the standard Antec 80mm ones, they are quite noisy it seems.
Thanks!

posted by ac to computers & internet (15 comments total)

These folks carry a variety of things that will help you out. In my experience, case fans are hardly necessary. I was particularly bothered by a shrill, high-pitched whine that I isolated to the stock fan on my graphics card. I replaced it with this heatpipe. I also went with Seagate hard drives with fluid bearing motors, which are much quieter than normal drives.

Ultimately, though, I switched to Macs, and am much happier than when I was fiddling around replacing things to eliminate noise.
posted by stonerose at 1:48 PM on February 22, 2004

BTW, Molex fans really are a whole lot quieter.
posted by stonerose at 1:49 PM on February 22, 2004

I'm a little confused by the question. Are you asking if it's safe to eliminate a few fans for the sake of noise? Are you asking what the sweet spot between silence and cooling is? Sorry to be so ornery about it, but something like "how many fans do I need?" is meaningless without knowing the specific detailed configuration of your hardware, build quality, case specs, and airflow and positioning of the fans you're using.

It sounds like this is a big, heavy box with plenty-o-hardware, and cooling should be your priority over silence. Shop around for bearingless fans with low noise ratings -- it's not hype, every device makes an amount of noise that can be quantitatively measured -- and consider undervolting some of your fans to 7VDC.

As far as I can tell from what seems to be your question, you are going to need to play around with cooling configuration. Remember it's all about flow rate: the more air you move in and out of the case, the better for cooling and worse for noise.
posted by majick at 1:57 PM on February 22, 2004

To add to the discussion, Silent PC Review is a great place for the latest in quiet computing. The recommended component lists, guides, and forums are a wealth of information. Basically, silent computing is about compromise--not getting the newest, hottest CPU, maybe getting a little bit slower hard drive, spending a bit more on high-quality fans. For example, do you really need three hard drives? Hard drives these days with fluid bearings are exceptionally quiet and are relatively high capacity. They don't really need auxilliary cooling, either.
posted by zsazsa at 2:12 PM on February 22, 2004

On a related issue (I have been struggling with the same problem), how hot is too hot for a PC anyway? I recently built a new machine at home and, with the hot weather we are experiencing recently, it is running at around 40c for the motherboard and 50c for the CPU, but it is quite noisy with the extra case fans I needed to get it down to that level.

It is easy enough to juggle fans, case placement etc to adjust the temperature, but I don't really know what the temperature should be.
posted by dg at 2:44 PM on February 22, 2004

One fan I can definitely recommend is the fan many cases have that blows air over your hard disk(s). Hard disks that are cooled last a lot, lot longer than ones that aren't. If you look at the stats, the difference is so significant that when I got an external FireWire hard disk for my Mac, I took the top off the case and rigged up a fan to blow over it. If your hard disk is too hot to touch, get a fan on it pronto.

As for CPU temps, mine (an Athlon XP 2400+ running Windows 2000 server) is typically 37-38 C. It's 42-44 C if I'm not running CPUIdle, which lets your CPU nap when it's not being used. Very good for Internet servers since CPU is rarely the bottleneck. My case temp is typically 34-35 and HD temp is 28-30.

50 C definitely seems a bit on the high side; I'd check to make sure you have a good interface between the CPU and the heatsink, with a thin layer of thermal paste. Every 10 C degrees of temperature cuts your CPU life in half.
posted by kindall at 2:56 PM on February 22, 2004

Due to my silent ways, my Athlon 1200's been running at 65C for about 3 years. Never had any stability problems whatsoever. Case temps vary, but are usually around 45C.
posted by zsazsa at 3:30 PM on February 22, 2004

Thanks for the info kindall - that gives me some benchmarks to work towards. Now, if only someone can tell me how to keep a PC this cool when the temperature of the room it is in hovers around the high 30c mark...

If it helps, ac, I suggest that you have a look at the air intake holes in your case - I found that the motherboard and CPU temp dropped around 4c by modifying the air intake slot which was on the bottom of the plastic front panel of the case and is the only intake for the two case fans in the front of the box. I enlarged this slot by cutting almost all of the bottom of this panel out and also put the box up on a wooden block to allow more air into the case (the carpet was mostly sealing off the air intake). By removing this restriction to the air intake, there was also a small but noticeable reduction in the noise level from the case fans.
posted by dg at 3:44 PM on February 22, 2004

Also, after speaking with the gurus at my local computer shop, they suggested building a duct from the outside of the case to allow the CPU fan to draw cool(er) air to the CPU rather than the hot air from inside the case, which makes perfect sense and would not add anything to the noise problem. This could be as simple as using some cardboard and duct tape, but I will be calling into the local hose supplier this afternoon and finding something suitable.
posted by dg at 4:41 PM on February 22, 2004

I am a big big big fan of Silent PC Review (SPCR, linked above).

Wire management allows for better airflow, so that is something you should look into. Switch to quieter Panaflo fans, or any of the others on SPCR's recommended list.
posted by riffola at 4:43 PM on February 22, 2004

Third that recommendation on SPCR. (And consider joining our Folding@Home team if you have a few cycles to spare--we're currently ranked #26 and can use all the help we can get.) Before you go nuts about replacing and/or fiddling with the fans though, what brand/model hard drives and PSU are you using? "Continuous, loud hum" could be anything from hard drives to power supply exhaust. Your PC is only going to be as quiet as your loudest component.

In addition to the molex fans idea, Zalman makes a fan controller with a control knob, and there are lots of fan control panels you can mount to your case's front bezel to drop the voltage (and noise) of your fans. The key to good temperatures is good airflow within your case. I also recommend the duct idea, except for I do the opposite and use the duct as an exhaust vent to keep the hot CPU air away from the rest of my components (especially video card and harddrives). It's not as good for your CPU temperatures as an intake is, but it's much better for the rest of the components inside your case and helps to maintain a cleaner front-to-back airflow pattern within your case. Also, obstructions on the intake side of a fan generate more noise than obstructions on the other side, so be sure to unblock/enlarge any grills/etc at your front intake as per dg's suggestion.
posted by DaShiv at 5:00 PM on February 22, 2004

Every 10 C degrees of temperature cuts your CPU life in half.

Does this go for laptops as well? My Dell Inspiron 8500 has been running consistently at about 50 Celsius. I use this utility which regulates the temperature better than the default Dell BIOS, but I would feel much more comfortable getting it down consistently to around 40 degrees.
posted by PrinceValium at 6:40 PM on February 22, 2004

The case is an Antec SX835-II, using the Antec power supply it came with. System is a P4 2.4Ghz, 1GB RAM, 3 7200RPM WDC Hard Drives, Radeon 9500 Pro Video card. The first case fan is located in the front bottom, behind the case's screen grille, and the second is higher up in the back, where there is a grille opening built in.

Are you asking if it's safe to eliminate a few fans for the sake of noise? Are you asking what the sweet spot between silence and cooling is?

I would like to know if its safe to eliminate the fans, but also what a good balance of heat/noise would be. How do I objectively measure the noise output anyway?

Kindall - I had two hard drives practically touching for a long time, and they were so hot I burned myself. I now have a fan blowing right over all three drives (which are extremely close together) and they are only lukewarm. I feel alot better about it now.

My software hardware monitor now tells me that the CPU is 46 C and the "System" is 43 C - the noise is alot better now, I think I will leave it for now. I am still uneasy about heat shortening the life of my components

Can anyone recommend any particular, specific 80mm that are really quiet? They don't have to be very big or fast.

The controller knobs - do I have to manually adjust those? Seems bizarre to me - do I need to like crank them up if I am launching a CPU-intensive program or what?

How do I measure airflow rate? What does "cfm" mean?
Thanks everyone for the help! This PC was expensive, but noisy, want to make sure I do everything right.
posted by ac at 8:05 PM on February 22, 2004

ac, get AIDA32 or Motherboard Monitor, and report back what your harddrive temps according to SMART are. That is of course if your harddrives support SMART and it's turned on.

Also list your specs, motherboard, CPU, RAM, video card, models of HDs, etc.

Panaflo's L1A 80mm fans are great, esp if you run them at 5V instead of 12V using either a fan controller or a Zalman fanmate.
posted by riffola at 9:04 PM on February 22, 2004

You want specs?! Eat this!

Intel Pentium 4 2.4Ghz Northwood CPU
AOpen AX4B Pro-533 Motherboard
Antec SX835II Performance Case
Maxtor 6Y060L0 60.0 GB 7200 RPM ATA/133 HD
2 x Western Digital WD1200JB 120.0GB 7200 RPM ATA/100 IDE HD
1024 MB DDR266 PC2100 SDRAM
ATI Radeon 9500 Pro 128MB
Viewsonic A90f+ 19" Flat CRT Monitor, 1280x1024 @ 75hz
Samsung SD-M1212 EIDE DVD-ROM Drive
LG CED-8080B EIDE 40x8x4x ATAPI CD-RW Drive
Realtek RTL8139 10/100 Integrated Ethernet Adapter
Avance 97 Surround 5.1 Integrated Audio
J-Bond JDC5010 PCI Fast SCSI-2 Controller
PC-Tel PCT789T 56K v.92 Modem
Creative Labs DXR3 PCI DVD Decoder
VIA OHCI-Compliant IEEE 1394 PCI Adapter
Iomega External SCSI Zip 250
MLi 699 Shielded Hi-Fi Speakers
NEC 1.44M Floppy Disk Drive
Coolmax CI-622 USB 2.0 Internal 3.5" SD/MMC/CF/MS/MD/SM Flash Card Reader
Uno! USB CompactFlash I/II and Microdrive Reader
Generic Stereo Analog Microphone
Microsoft Wireless Optical Mouse Blue
Solidtek Precision ACK-260A PS/2 101-Keyboard
Radioshack 33-1176 Stereo Headphones
Microsoft Windows XP Professional SP1
Microsoft Office XP Professional
Microsoft Visual Studio .NET Enterprise Architect
Microsoft Visual Studio 6.0 SP5 Enterprise
Symantec Norton AntiVirus 2004 Professional Edition
Symantec Norton Internet Security 2004 Professional Edition


Oh and thanks for the fan tip.
What is AIDA32? Google is down right now I swear to god - its 5:19 PM EST and I can go to Yahoo.com but not google.com... this is unsettling.

They do support SMART, I will look into it. How does that work exactly, I could never figure it out.
posted by ac at 2:20 PM on February 23, 2004