I had hoped to title this thread using the word silent, but I just couldn't get it there. I've been tinkering with my new Shuttle Zen everyday since it arrived, tried new parts only to end up trying something different. I even ordered parts that, by the time they arrived, I no longer needed. In the end, my final stratigy was to go completely fanless. And happily was successful.
I decided to see if the computer would boot if I underclocked my 3.0C to 1.5Ghz using a 100Mhz bus and undervolting it to the minimum offered in the bios, 0.8250v. Amazingly, at least to me, it booted. I immediately disconnected my fan from the housing but left it hooked up to the motherboard so I could test the voltage being sent to the fan. The fan was left completely outside of the computer and blowing away from it. At present there isn't any software available to read the cpu temp within Windows, so using the Smart Fan "ramp temp" setting in the bios along with monitoring the fan is the only way to get any idea how hot the cpu is running. This turns out to be enough, though cumbersome. After dismounting the fan I ran two instances of CPUburn for two hours without the motherboard ever ramping the fan. This means the cpu never reached 60C, the "ramp temp" I have set in the bios. I thought this is looking real good!!
Next came Prime95's torture test. This test didn't fare as well. In a little over four hours Prime95 encountered an error. Rats! Not stable. I went back to the bios and set the Vcore up one step to 0.8375v. Another shot with CPUburn revealed no fan ramp. And best of all, Prime95 ran 36 hours error free. It was stable!
There were a couple other things I learned while all this testing was going on. The first was that the case cover had to be removed. With the cover in place it turned into a little oven and ramped the dismounted fan, meaning the cpu climbed above 60C. The next thing I learned is that the hard drive that I had suspended below the floppy bay was getting cooked by the chipset heatsink and ram even with the cover off. Its temp climbed to 58C where I shut it down. I then rigged up a suspension in the 5.25" bay and the temp stablized at 45C. As a side note, even though it's posted over and over again how hot the Seagates are it slipped right past me. I learned after I installed it though.
So what I had learned at this point was: The Zen can be run without a fan, the cover needs to be either very well ventilated or removed, and the only place in the computer that a hard drive can be kept without a fan is in the 5.25" bay. But wait, we have a problem. That 40GB Seagate 7200.7 ain't so quite when it isn't being drowned out by a fan. Not only that, the extra heat it's dumping in the case is all the more that's going to have to find its way out passively through yet to be created case vents. So, to the delight of yet more online venders, I purchased a recently reviewed Toshiba 40GB notebook drive, a 3.5" to 2.5" drive adaptor, a Smart Drive enclosure, and some wire fan grills.
To maximize passive ventilation I decided to use the USB optical drive that I fortunately already owned and to leave the Smart Drive enclosure outside of the case. The stock IDE and power cable are long enough to reach out the PCI slot with its cover left off. I cut some holes, installed some grills, hooked up my drive, and this is what we have:
There is a matching pair of wire grills on the other side of the case as well. I also placed a wire grill over the hole created when I previously cut the grill from the case that covered the ICE radiator. I did this to protect the radiator.
A picture of the wide open spaces:
I used a piece of foam to secure the notebook drive in the Smart Drive. You have to actually get one of these drives in your hands to appreciate just how small and light they are.
Drive temps have never climbed above 31C with the Toshiba in the Smart Drive using the foam under the drive to secure it. It seems to get enough cooling just having the top in contact with the copper.
This system is exceptionally quiet. It's not silent, but with even the slightest background noise the only faintly audible part of the system, the hard drive seeks, become inaudible. It's certainly slower than it was, both because of the underclock and because of the notebook drive. It's more than suitable for most if not all of my needs. Those with intense cpu or drive demands should look the other way.
I'm going to post wattage demands measured with an amp meter at the PSU power cord. I've already discovered that my watt measurements don't measure well against those that the reviewers here are finding. I can't explain why, nor do I doubt the reviewers. Nor do I have any reason to distrust my amp meter. So here they are:
Idle Desktop: 28 watts
CPUburn: 38 watts
Mind you that this is the power being drawn from the wall socket. That means there is even less being delivered to the computer because of the inefficiency of the PSU. I attribute the figures above to three things: 1) The extreme underclock & volt. 2) The Toshiba that draws under 3 watts. And 3) My usb optical drive has its own power supply.
Anyone interested in this very quiet system could tinker with the clock and voltage to see how high the system will go and still not need a fan. You can test this without cost if you have a Zen. Just remove the fan, remove the drive, remove the case cover, and get clocking! As for me, I'm tired of testing and tired of taking things apart and putting them together again. I have half my basement in my office. It's time to put everything away and enjoy the peace I have found.
My thanks go to our hosts and all the contributors of these forums. Without those contibutions the above would not have been possible. I hope that the inclusion of this recipe for quietness finds its way to help another.