Enjoy the Silence

"My journey to PC modding insanity and back."

By Simon Edwards <simon@simonzone.com>
Sunday, 10 August 2003

Initially this little side project started out more as a bit of general maintenance. I run my machines 24/7 and they tend to collect quite a lot of dust. I've seen enough fans fail and take the CPU/motherboard with them to know that they really must be regularly replaced. Especially when it is the case of a cheap standard CPU cooler costing basically pocket-change being expected to cool and a CPU costing a hundred times the amount. The cheaper AMD Duron processors don't have a thermal shut-down system in place. If they get too hot they just cook to death.

A few months ago the fan on the graphics card of one of my machines failed, so I removed it and operated the machine with the case open. Obviously this could only be a temporary solution so I tried to find a real one. I found a "slot cooler" which is just a fan that fits in a card slot and removes air from the case. It was so unbelievably loud! That is when I cracked. That is when I found my mission.

After doing some searches on the net for replacement graphics card fans I found a a very interesting site - Silent PC Review. It gave me ideas and the rest just flowed from there... Little did I suspect that it would become small-scale obsession for a while...

Original System specifications:

Step 1: Drive Suspension

This article, Hard Drive Silencing: Sandwiches & Suspensions at Silent PC Review kicked off my stealth mission under-the-hood. Suspending a hard drive is a very effective way of stopping vibration from the drive being transferred to the case and then the case acting as a big speaker box and transmitting the noise. Doing this was cheap and pretty easy, and reported to be very effective. So I went to the local sewing shop and then gave it a go.

Suspended Drive

First attempt. Later I discovered that the cord that goes under the drive and holds it up really needs to doubled up in order to keep the drive vertically centred in the drive bay area. (Four cords going under the drive instead of two).

Results: As reported by others, the results were quite dramatic. The annoying high pitch whiny noise from the hard drive had been considerably reduced. It was very surprised really. Everyone should do this. Also seek noise (a.k.a. "That grinding noise the computer makes when I want it to start stuff.") had been mostly eliminated. It's freaky not hearing anything when the computer boots up.

Tip: You probably don't need to buy 10 meters of elastic cord. :-)

Step 2: Actively Passive

Moving parts cause noise. Active cooling systems such as fans cause noise. Get rid of the moving parts and you get rid of the noise.

The only real thing in the computer that could be replaced with a passive solution of some kind was the graphics card fan. I had had already trouble with graphics card fans failing and causing system instability and realised that the best way to stop a graphics card fan from jamming is to throw it in the bin and replace it with something other than a fan. I chose a Zalman ZM-NB32J Northbridge heatsink. They are intended mainly for use on modern motherboards, but the ZM-NB32J can also be used on other similarly sized chips.

Passively cooled GeForce 2 card

Here is the Zalman ZM-NB32J on the GeForce2. The card even had holes in just the right places for the heatsink's mounting pins.

The only downside of using this heatsink on the graphics card is that it costs you the adjacent PCI slot in order to fit the card in the case. This wasn't a big deal in my situation. Another thing worth mentioning, the heatsink didn't make very good contact with the graphics chip. After first attaching the heatsink I examined my work by holding the card up to the light, looking for any gaps between the heatsink and the chip. The chip was plastic cased and seemed to be raised at the corners slightly, stopping the heatsink from making direct contact. I just solved this using a thicker layer of thermal paste.

Results: Doing this didn't seem to affect noise production too much, but I do feel better knowing that the graphics card is properly cooled and can't jam up.

Step 3: CPU

The heatsink fan perched on top of the CPU is one of the main causes of noise. These fans are generally not very big, meaning they produces high pitched sound, and must also run at high speed. They also happen to be one of the components in a system those job it is to protect the most expensive part of the system from bursting into flame. Now is not a good time to be 'cheap'.

After some research I settled on a Arctic Cooling Copper Silent TC CPU cooler. It is quite standard in design, meaning that installation is straight forward, although it's not very visually interesting (This is not a fashion parade here.) The cooler is thermally controlled meaning that the fan runs fast only when it needs to, but when the CPU is cold, like at boot time, it doesn't even run at all. (But it thankfully does when the CPU warms up. =) )

Old and new CPU coolers.

The new Arctic Cooler on the left compared to my old "cheapest-China-can-make" standard CPU cooler. Sometimes bigger is better.

Result: The biggest change was that now the CPU operates at around 49 C instead of around the 59 C with the older cooler. (Note that Intel CPUs typically run 10-20 degrees cooler than the temperatures here). The overall system is quieter than before but it is now dominated by the sound of the power supply fan and also the hard drive to a lesser degree.

Step 4: Liquid Drive

I needed a new bigger hard drive. MP3s and a digital camera mean that I've got a lot more data than in the past. This provided a good opportunity to buy a new and quieter hard drive.

The conventional advice on quiet hard drives is simply Seagate, end of story. They basically invented the whole drives-that-don't-sound-like-chainsaws market niche. But that is already a while ago and now other manufacturers are using quiet technology in their drives. Now especially since people are building 'media centres' or 'jukeboxes' and moving PCs into their living rooms.

After doing some shopping around to see what drives were available, and checking Storage Review's Benchmark Database to find out which drives are likely to quiet, I ended up buying a 120 Gb Maxtor DiamondPlus 9. It's reasonable compromise between size, performance, availability and noise. The drive uses fancy new 'liquid bearings' which are meant to go a long way to eliminating noise.

Results: After a lot of trouble moving my Windows and Linux partitions across (mainly trouble with Windows) I had everything working. The drive was suspended, but not in a closed case yet. The most striking thing about this drive the amount of heat it produces. It runs at 7200 RPM and is one of the hottest drives on the market. You can barely pick it up after it was been running for a while. Yes it's that hot, almost too hot for touch. Perhaps the whole 'liquid' label that is attached to this drive refers to how it could melt into molten slag at any moment. This is not a good thing, although it probably explains why drive warranties have all now been reduced down to 1 year by all manufacturers. But despite this downside, the drive is big, fast and quiet. The high pitch whine noise is very soft. You really need to move your head close to the drive to hear it. Inside a case it can not be heard. The sound it makes when the drive is seeking, is actually quite loud. Drive suspension eliminates most of this noise, and quite honestly it doesn't bother me. It's not very loud nor is it constant or irritating.

So leaves me with a computer that I don't dare reassemble for fear of melting the hard drive. Time for some cooling, and how can I get that power supply to hush up?

Step 5: Fans & Cooling - The Final Showdown

Time to wrap the whole project up. Replace the fan in the power supply to get rid of the remaining source of noise, and also organise some direct cooling for the new hard drive.

The popular Panoflo fans are not easy to come across in Europe, although Papst fans are. I also wanted to be able adjust the speed of the fan too. In an attempt to keep costs down a bit I ended up going for a couple of 80mm Enermax UC-8FAB fans. They are not too expensive and are also speed adjustable out of the box so that you can turn them right down. This is about half the price of going for a combination of a Papst fan and a Zalman Fanmate.

I actually swapped the power supplies on my machines around a bit. The Duron was using a high quality 420W PSU that I didn't feel like hacking. So used a 300W supply from another machine and carefully replaced its fan with an Enermax. The supply only had a fan and grill on one side plus another pressed grill at the other end, the intake grill. What I needed was for the supply to be able to take air in through its bottom where the motherboard and CPU area will be located and exhaust that. I used a power drill to drill some holes in the bottom of the supply cover to provide another intake grill.

Now, the hard drive needed to be mounted with elastic cord in a 5.25" bay, and at the same time have a fan on it. Normally you can put a fan on the air intake hole in the front bottom of the case, and put the hard drive just behind that. My case doesn't have a 'rack' or anything at the front bottom of the case, but I did have a lot of free space in the 5.25" bay area, all I had to do was mount the fan there. Out came the hacksaw, file and power drill and after bit of cutting and fitting I had the fan mounted on two plastic 5.25" bay covers. Note that my case has a door so I could not mount the fan entirely in front of the hole in the bay covers. Also the hard drive in the bay didn't leave a lot of space at the front of the case either. So I mounted the fan with the the plastic covers wrapping around the fan. It gave just the right amount of space on both sides for the door and the hard drive.

HD fan

Originally at this point the fan was positioned a couple of bays lower.

Results: Testing with the case open, the fan in front of the hard drive kept it down to the highly scientific temperature of "slightly warm", which is much better than the earlier temperature of "too hot to handle". Much better, although it still made a bit too much noise even when turned down all the way. The Enermax fans can be connected to power using standard 4 pin PC power connectors which makes them easy to hack to use 7 volts instead of the usual 12. On 7 volts I can turn the fan down enough that it really is quiet.

Step 6: Airflow - Back to School

There was never meant to be a step 6. After I had my machine all put back together I was still not quite happy enough with it. The power supply fan still made quite a lot of noise, but what was worse was that my CPU temperatures and case temperatures were about 5 degrees higher than before. What went wrong? After a bit of thinking about what might be going on in the case with respect to airflow I realised that the air from the hard disk fan is more of less being pumped directly into the power supply. What this meant was that the lower air pressure caused by the power supply fan was being cancelled out by the high air pressure coming from the hard drive fan. Air was moving alright, from the hard drive fan to the power supply, but not from the motherboard/CPU area to the power supply, and certainly not from outside the case into the motherboard/CPU area.

First part of the solution was to improve the airflow through the power supply. Its exhaust fan was covered by a grill cut into, or pressed out of, its metal case. The grill didn't seem to do a very good job. (Like this one here.) About 50% of the area over the fan was still covered by metal. Four snips with the tin snips and it was out of there! I removed the whole grill area. Now the fan can do its job.

After a second look at my handy work of adding some air intake holes to the power supply, I concluded that it just wasn't good enough. The holes were too small and there were just plain not enough of them. I had a few spare wire fan grills laying around so I thought "Why not just install one of those?". I cut out a hole for the wire grill in the power supply case using a power drill, a hacksaw and finally when I had a big enough hole, using tin snips. The hacksaw didn't work very well, but to my surprise the tin snips worked great despite being huge. After some more work with the power drill, I screwed the grill on. It doesn't look half bad, if I do say so myself.

I also set the fan for the power supply onto 7 volts.

Vented PSU.

PSU with exhaust grill cut out and wire covered intake hole for the CPU/motherboard.

That just leaves the problem of the hard drive fan feeding the power supply. My solution was to isolate the two air/fan systems. I moved the CDROM drive and CD burner down into the bottom two bays, and moved the hard drive and fan up into the top. Then using a piece of space age air isolation material, I put in a barrier between the hard drive area at the top of the case and the power supply/motherboard area at the bottom of the case. (See picture below).

Wind Tunnel Picture

The hard drive fan (top right, not visible) sucks in air over the hard drive and towards the back end of the case where it exits via the built in fanless grill.

The power supply, now free from obstructions and lousy grills can now happily move air into the case via the motherboard area and out via its exhaust.

Results: With the case closed up and the power supply fan turned down, the CPU temperature is once again around the 49 C degree mark, and the power supply is also finally quiet. Looks like the work on the airflow really paid off.


Well, it took a lot more time, effort and money than I initially expected, but my machine is now quiet enough. With typical daytime noises like the neighbours, or the TV on in the other room, the machine is practically inaudible. Late at night with things like the TV off you can hear the fans, soft but still there, although it's not really annoying either. I'm confident that everything is sufficiently cooled, and I also have a new big and fast hard drive. =) Excluding the cost of the hard drive, the cost of the whole exercise was a bit over the 100 euro mark. As for time the whole thing cost bucket loads of it. That's counting all of the research and installation. But in the end I'm happy with it, I learnt a lot and it didn't cost too much. Worth doing.

Thanks go mainly to Silent PC Review and the volumes of information and tips contained in its forums.

Simon Edwards