Silencing a P4-1.6A oc'd to 2GHz

Do-It-Yourself Systems
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System Components

  • Intel P4-1.6A Northwood core retail P4 heatsink & fan
  • MSI 645 Ultra 333 motherboard
  • 2 sticks of Elixir 256MB DDR-266MHz-CL2.5 memory (generic)
  • ATI Radeon VE 32MB video card
  • Seagate Barracuda IV 40G hard drive
  • SH ATX365P4 365W power supply unit
  • 10/100 network card
  • Floppy drive
  • Soundblaser 4x2x24 CD-RW drive

Noise Sources

1. HSF

As mentioned earlier, I would try the retail HSF at stock voltage, and then experiment with lower voltages, resorting to a different fan or HS only if necessary.

2. Power Supply

Aside from the heatsink fan, there are two other fans in these components, both of them in the SH ATX365P4 power supply, a 365W unit similar to the Enermax PSUs. The SH brand is associated with Superpower.com which also imports Landmark ATX cases into the US. A couple of emails sent to Superpower went unanswered, so I can only tell you what I learned first hand about this PSU.

  • It has a goodly number of IDE power connectors (sorry, didn't count them all), plus the 4-pin P4 motherboard connector on generous lengths of lead, though not quite as long as the Enermax PSUs.
  • The normally positioned 80mm fan blows the air out of the PSU and the case.
  • The second less powerful 80mm fan is positioned perpendicular to the first fan and draws air into the PSU from the area directly above the CPU when mounted in a typical ATX tower case.
  • The two fans act in push-pull fashion. In this configuration, the overall airflow is theoretically not greater than that of the more powerful fan in free air. But it does provide greater pressure, which can help move the air more effectively through the obstructions within the PSU.
  • The speed of both fans is controlled by a single thermistor.

I used a jumper to start the PSU without a motherboard in order to listen to it. The PSU fans are fairly quiet upon start-up. However, even without any load on the PSU, both fans accelerated to a much higher speed within 10 minutes and the noise emitted by the PSU became more considerable. Modest by normal PC standards, but unacceptable by the standards of Silent PC Review. This in a room where the temperature rarely exceeds 20? C.

I decided to modify the PSU before assembling the system by removing the second fan, repositioning the internal thermistor away from the hot coil to which it was glued, and replacing the first fan with my standard quiet fan, a Panaflo 80mm FBA08A12L. Note that opening up the case voided the manufacturer's warranty on the PSU and exposed me to some danger from electrical shock. I worked with the AC cord unplugged, of course. (Please see my article about silencing PSUs with thermistor-controlled fans.) BTW, the Panaflo fan is probably the most popular quiet fan among silent computer builders and modders: rated at a low 21-dBA, 24 CFM airflow, and widely available for as low as $3 from some US web retailers.

When the modification was completed, the noise of the PSU dropped to the level of a whisper and never rose under any condition. Yet the soft airflow from the Panaflo fan in the PSU never got more than warm. It became inaudible inside the case when placed under my desk.

3. Drives

The other noise makers among the components were an older 4x Creative CD-RW drive and a Seagate Barracuda IV 20G hard drive. The slow CD-RW makes little noise and is of consequence only when it is being accessed, so I would install it normally. The Seagate Barracuda IV has been the quietest 3.5" hard drive available ever since it was introduced in the third quarter of 2001.

In my experience with a large variety of other 5400 and 7200 rpm IDE drives from IBM, Maxtor, Quantum, Western Digital and even Seagate over the past several years, nothing comes close to the single platter 20G and 40G Barracuda IV models I began using late last year. With noise rated at a vanishing low 20 dBA while idling, the most notable aspect of these 7200 rpm HD is the complete absence of the high pitched whine that characterized all other 7200 rpm drives in my experience to date.

Still this does not mean the Barracuda IV cannot be made even quieter.

I recently devised an elastic suspension system for hard drives. It ensures that the noise of Barracuda IV remains unchanged even when mounted in a case, which usually amplifies drive noise by resonating and vibrating in sympathy. This suspension would be used for the Seagate. (See this article on hard drive silencing.)



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