My First Mac

Overheated IBM Leads to Air Cooled iMac

John Twelker - 2001.07.03

My first Mac was a 500 MHz iMac. What impressed me was the cool running OS and the peace and quiet of the convection cooled iMac.

My 13 month old IBM Aptiva came with Win98 preloaded. However, I installed and used OS/2 and Linux because of their power, stability, multitasking and protected memory. I kept Win98 so my grandson could play Myst and Riven.

One day a friend asked why I used OS/2 and Linux, and I demonstrated Win98's weak virtual memory manager by loading several large applications and downloading a couple files, then began formatting a floppy - and one more double click on another application resulted in the screen going black and the computer turning off. From then on, Win98 would only stay up about 20 seconds before shutting down. Cooler running OS/2 and Linux would stay up several hours before the computer shut down.

I checked the Internet and found that Win9x changed the default processor setting and was basically running overclocked, resulting in an extra 25% heat buildup (see below) which could stress hardware components - the processor, hard drive, video card, etc. Apparently, my Aptiva's processor suffered a heat stroke.

I contacted IBM, and the only help they could offer was a suggestion to add another fan. I reminded them that this wouldn't resolve the heat damaged processor problem and suggested the Aptiva with only two fans was under-cooled in the first place. They said that this was not a "known problem," to which I replied, "Now that I've told you, it's known!" They replied, "It's known when it appears in our reference book. and since it doesn't, it's not a known problem."

I was so disgusted with IBM that I went down to my local Apple reseller and bought my first Mac. When OS X was released, I immediately bought it and installed it. In my opinion, OS X is a great OS; I already like it better than OS/2 and Linux. I can do everything I need to with my iMac and OS X.

The only thing I look forward to is an iMac with a LCD screen!

Aloha from Maui.

Stressing the CPU

Twelker's comment on Windows stressing the CPU was news to me, so I tried to find some information on the Web. Neither Sherlock nor Google was helpful, but John Twelker sent me the link to OS/2 and the Real World by Tom Nadeau.

Like Mac users, OS/2 users fall into two overlapping camps - those who just want to get the job done and the "anything but Microsoft" group, which tends to be more vocal. Like Mac users, they know they have a better OS than Windows.

But here's the information referenced above (emphasis added):

Most people readily admit that Windows is cranky, cantankerous, and unpredictable. Yet that is only from the user's perspective, based on regular software crashes. There are deeper issues involved. For example, the Windows9X systems are DOS-based; they must switch from 16-bit DOS real mode to 32-bit protected mode dozens of times per second. This switching process puts a lot of wear and tear on the CPU and other system components. In addition, Microsoft has disabled the standard CPU clock cycle mechanism recommended by Intel: 3 cycles on, one cycle off for cooling purposes. By removing the cooling cycle from Windows, Microsoft was able to speed up the apparent performance of these OS's by 33% (1 extra clock cycle available for every 3 that other OS's would use). Yet this did not make Windows faster than other OS's; it merely reduced the performance gap that would otherwise have made Windows a laughingstock. Windows is still a slow operating system, but not as slow as it otherwise would be.

The disadvantage of this trickery is that CPUs running Windows operating systems tend to operate at 10 degrees to 20 degrees hotter than CPUs running "normal" operating systems that don't cheat against the Intel specification. This extra heat not only wears out the CPU faster, but also spreads throughout the inside of the PC case, threatening to reduce the life expectancy of other heat-sensitive components such as RAM, motherboards, VGA cards, and power supplies.

Don't believe it? See Windows 98 Does Not Support ACPI Passive Cooling Mode on the Microsoft site, which states, "Windows 98 configures the computer to operate only in Active Cooling mode, and does not provide an interface for changing the active and passive cooling set points so that the computer could be reconfigured to operate in Passive Cooling mode."

Why does Intel design such hot processors that they need to rest for one cycle in four? Good question. Ask Intel.

Why does Microsoft push the CPU beyond the manufacturer's recommendation? Tom Nadeau says it's because Windows would be too slow otherwise.

This implies that Intel-based computers might last longer with OS/2 or Linux installed. Of course, Windows users tend to get locked into a three year or so upgrade cycle, so that may not really be an issue.

On the other hand, overriding the manufacturer's recommendation probably means the CPU draws more power. It definitely means the computer itself must dissipate more heat, which also draws more power. With the threat of a national energy crunch, it seems irresponsible of Microsoft to do this.

I'll stick with my energy efficient Macs.

Dan Knight, publisher, Low End Mac

Go to the My First Mac index.