On Jan 1, 2004, at 2:35 PM, Eric S. Johansson wrote:

Tim May wrote:

...

I'm skeptical of this claim. A lot of Intel and AMD and similar machines are running full-tilt, "24/7." To wit, Beowulf-type clusters, the Macintosh G5 cluster that is now rated third fasted in the world, and so on. None of these machines is reported to be burning up literally. Likewise, a lot of home and corporate users are running background tasks which are at 100% CPU utilization.

I will admit to a degree of skepticism myself even though I am describing overheating as a likely outcome.

But what is your actual evidence, as opposed to your belief that overheating is a likely outcome? I have said that I know of many machines (tens of thousands of CPUs, and probably many more I don't know about directly) which are running CPU-bound applications 24/7. I have heard of no "burning up literally" cases with the many Beowulf clusters, supercomputers, and 24/7 home or business screensavers and crunching apps, so I suspect they are not common. If you have actual evidence, as opposed to "likely outcome" speculations, please present the evidence.

First, if you lose a fan on an Intel CPU of at least Pentium III generation or an AMD equivalent, you will lose your CPU to thermal overload. This is a well-known and well-documented problem. One question is can stamp work thermally overload and damage a CPU. Second question is how much stamp work can you do without thermally overloading the CPU.

This is true whether one is running Office or a stamp program. You are just repeating a general point about losing a fan, not about stamp generation per se. Boxer fan lifetimes are usually about comparable to hard drive lifetimes, which also kill a particular machine. You are not presenting anything new here, and the association with stamp generation is nonexistent.

Large clusters have more careful thermal engineering applied to them than probably most of the zombies out there. I have seen one Beowulf cluster constructed out of standard 1U chassis, motherboards, fans etc. and frequently 10 percent of the systems are down at any one time. The vast majority of the failures have been due to thermal problems.

Most clusters use exactly the same air-cooled machines as are available from Dell, Sun, Apple, etc. In fact, the blades and rackmount systems are precisely those available from Dell, Sun, Apple, etc. You are presenting no evidence, just hypothesizing that your stamp protocol somehow burns out more CPUs than render farms do, than Mersenne prime apps to, than financial simulations do, etc. Yet you present no actual numbers.

so, will we see a Pentium IV spontaneously ignite like a third tier heavy-metal group in a Rhode Island nightclub? No, you're right, we won't. I think it's safe to say we will see increasing unreliability, power supply failures, and failures of microelectronics due to increased thermal load. Which is good enough for my purposes.

Evidence is desirable, belief is just belief. --Tim May "That government is best which governs not at all." --Henry David Thoreau