John Martellaro Examines The Megahertz Myth

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One of the most ubiquitous terms in the computing world today is the megahertz myth. OSXFAQis John Martellaro, however, takes a new look at the myth with respect to the G4, the Pentium, and Apple. His thoughts incorporate his experiences while employed at 1 Infinite Loop. From the article:

One of the things that I learned in my 21 months at Apple is that the G4 is a very capable CPU for mathematically intensive scientific and engineering calculations. This is because it has a very well designed SIMD processor for vector operations. In many cases, researchers who contacted Apple have supplied example vectorized code or performance data showing how a G4, running at half or a third of the clock speed of a Pentium can out perform the Pentium. Theyive been able to do this because 1) theyire smart, 2) they love the Macintosh platform, and 3) theyive figured out how to exploit the tool they love. I call this effect TSLE, technical smart love exploitation. TSLE can achieve miracles you never thought possible on a Macintosh. Or any computer.


Then there are those researchers who lament that they must maintain portable code, and they donit have time to delve into the gory details of vector programming - which would muck up their code base. They simply want the fastest scalar processor they can get their hands on, whether itis an Alpha or a Pentium 4 running at 2.8 GHz. Thatis a justifiable position, but it could have been remedied had there been sufficient resources within Apple to create and maintain a robust Advanced Computing Group that could build development tools. Tools that would assist all comers, make their life easier with the G4, and put real understanding and technical tools in the hands of anyone who needs them. Alas, Apple likes to tout the power of the "Velocity Engine" but cannot afford to actually make it an exploitable tool for everyday scientific users. As a result, the G4 capability, at any clock, remains vastly under exploited. What remains is TSLE.

Mr. Martellaro continues his discussion of the megahertz myth with the traditional explanation that most users do not need the computing power of a 2.8 GHz Pentium 4 or similarly-clocked processor. Todayis typical consumer use does not require such raw horsepower. He returns shortly to conclude that more could be done to exploit all of the capabilities of current processors (such as the vector unit in the G4) rather than constantly push for faster and faster clock speeds. Where does this put Apple?:

Apple is a small company, relatively speaking. Its Fortune 500 rank is in the nether regions at #325. Currently, insufficient resources can be applied to make the full exploitation of the Velocity Engine a no-brainer for vast numbers of users and developers. Consequently, for the time being, if you want to get the ultimate performance out of your Mac, youill need to do research, study, practice, and work with colleagues. Resources to do this are listed below.

You can read all of Mr. Martellarois thoughts on the megahertz myth in the OSXFAQ article.

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