Mon, 09 Oct 2000

Adventures in running the CPU faster by keeping it cool

By Zatni Arbi

JAKARTA (JP): Two weeks ago I wrote about my new PC in this column. A friend, Raymond, e-mailed me, questioning why I chose the 733 MHz Pentium III and not a faster one instead.

He made a very good point: "Once you've installed the CPU, it will cost you more to upgrade to a faster processor."

My reason for choosing the 733 MHz was simple. I was trying to keep my budget under control. At the time I bought the components, the price of an Intel Pentium III processor running at 733 MHz was almost the same as the one running at 700 MHz.

Faster processors, such as the 750 MHz and 766 MHz, would have cost a lot more, and, as I wrote in that article, I would be happy with anything faster than a 600 MHz. So I thought the 733 MHz would have given me plenty of overhead.

There was a special feature of the motherboard that I had not tested before I wrote the article, although Astrindo's Alfredo Hui had explained it to me and I mentioned it briefly in my article. The ASUS CUSL2 is a great motherboard for overclocking.

Raymond's e-mail prompted me to try it out. The results made me happy. I was able to raise the internal clock speed of the 733 MHz processor to 929 MHz. Intel would scold me for telling you this, but I have had no problems so far.

The motherboard allows us to set the speed using its DIP switches or its BIOS. I chose the latter, because it was completely problem free. The BIOS lets us increase or decrease the speed in small increments.

I chose 929 MHz because it was the closest to being below 933 MHz, which is the fastest Pentium III that the motherboard supported, according to the manual.

The Case

To safeguard the system from getting overheated and having a short life, I decided early on to use a high-quality case. As I wrote in my article, I had my mind set on a mid-tower Elan Vital case, as it was recommended by three other friends besides Alfredo.

At Elan Vital's website, I learned that the most popular model was the T-10. Last week, Alfredo informed me that he had received a new shipment of this case, so I went to his store and bought one.

"The power supply is very good," explained Alfredo. "That's why the price is quite high."

The T-10 cost me more than Rp 1 million.

The case is not pretty. It is a rather dull box and does not have any fancy transparent panels or colorful buttons. The front face looks as if it was a piece of military equipment.

However, it is well-built. There is only one thumbscrew to lock the right side cover in place, although system administrators can use a padlock to keep it from being opened by unauthorized staff members.

The steel is far thicker and heavier than the Rp 195,000 case I bought earlier. It has three 13.3 centimeter (5 1/4 inch) bays that can be accessed and only one accessible 8.9 cm (3 1/2 inch) bay. I wish it had more internal bays, though, because I was planning to use an old Quantum ProDrive 2 GB SCSI hard disk that is a bit thicker than the other hard disks. Now I might need some tape to stick it to the bottom of the case as there is no more space for it in the bays.

The case also has two places for additional fans, which can be connected to the motherboard and monitored by ASUS' PC Probe utility. The boxes for the three 13.3 cm external bays and the three 8.9 cm bays can be easily taken out so that installing components, such as the CD-ROM drive and the floppy diskette drive, is easy.

Opening the front face is easy, too. There is only one button in front, which is the power button. It has to be turned 90 degrees clockwise before it can be pushed, so this will prevent an accidental power shutdown. The reset button is hidden inside the face, so I had to use a paper clip to reboot the system. The power supply at the back has a master switch, too. Clearly, this is a heavy duty case for serious computing.

Whispering fan

While I was at Alfredo's store, I also bought a special fan and an air duct also made by Elan Vital. The fan, called Whisper, is intended to blow cooler external air directly into the CPU. As you can see in the accompanying picture, the air duct channels outside air into the CPU. The theory is that external air is cooler than the air inside the case, because the motherboard already generates a lot of heat as well.

Right after I got home, I transferred the system into the new case. The fan that came with the Intel processor was too big for the Whisper, so I had to replace the entire heat sink and the fan unit. Installing the new unit was much easier than Intel's cooling fan and heat sink because the latch was designed better.

After all the cables were connected, I powered it up and, after awhile, I checked the temperature of the CPU and the motherboard.

The PC Probe can collect historical data, and I always turn this feature on. There was not much difference in the temperature of the motherboard. It fluctuated between 38 degrees Celsius and 39 degrees Celsius, almost the same as when I was using the cheaper case.

However, the CPU was now much cooler because the room was air- conditioned and the air conditioner happened to be located near the back of the case. Before I overclocked the CPU, its temperature was between 18 degrees and 20 degrees. After overclocking, its temperature jumped to between 35 degrees and 38 degrees.

But after I installed the Whisper, the CPU's temperature went down again to 18 degrees Celsius. It sometimes went as low as 13 degrees, which is extremely good for an overclocked processor.

Spinning at 3924 rotations per minute (rpm), Whisper's fan has a lower rpm than the fan that came with the CPU, which spins at 4787 rpm. Elan Vital used a lower rpm to keep the noise level at a minimal and make the fan last longer. Besides, the effectiveness of the fan is not determined solely by the speed at which it rotates.

The new case and the Whisper fan helped keep my new PC cool and allowed me to overclock it. I might add two fans later to improve air flow and lower the motherboard's temperature, which now stays at 38 degrees.

By the way, PC Probe's default maximum threshold for the CPU's temperature is 72 degrees Celsius, while the motherboard's is 60 degrees.

The bottom line is by using the right motherboard, we can save a little by buying a less expensive processor and forcing it to run faster.

However, you will also need the right case -- one with really good ventilation -- to prevent the motherboard and CPU from overheating. Overheating will not only cause the system to freeze, it can also damage it.

What's next?

What else is there to add? ASUSTeK has an interesting add-on feature for the front panel of the CPU. It has several buttons that can be programmed to invoke a browser, an e-mail client, etc. It also adds two more USB ports in front, which are useful for connecting a digital camera and a PDA, like Compaq's iPaq Pocket PC.

A version of this panel, which ASUSTeK calls the iPanel, has three audio ports. With this type of iPanel, we no longer have to reach to the back of the CPU to connect a headset if we want to use a voice-recognition program or communicate by PC telephony.

Once again I will have to wait as Alfredo does not have the iPanel available at this point.

I will probably go for Plextor's PlexWriter 12x10x32X CD- Writer, which Raymond recommended in his e-mail. Several web editors have been speaking highly of it as well. (