Measuring CPU speeds ( was RE: Why isn't Apple releasing patches for the Month of Apple )

Jim Leonard trixter at
Tue Feb 13 22:27:11 CST 2007

aliensrcooluk at wrote:
> Speaking of Dhrystones.... what is one?

There is no "one".  Like most benchmarks, Dhrystone is best used as a
means of measuring performance differences in like environments (ie. "I
increased the clock speed and now I get XX more dhrystones" or "I
optimized the compiler and got a few more dhrystones", etc.).  It is not
a platform-agnostic absolute measure.

> Also, what does the MHz, or GHz, measure
> exactly?

The number of machine cycles per second.

> I understand MIPS (Million Instructions Per
> Second), FLOPS (Floating-point Operations Per
> Second) and G-FLOPS (Giga-FLOPS) but the
> aforementioned two are a mystery to me.

Well, I don't like MIPS that much for the same reasons outlined in my
first paragraph.  For example, most 6502 instructions run in fewer
clocks than like instructions in 8088, but 8088 has 16-bit operations
for "free"... etc.
Jim Leonard (trixter at  
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