Int vs. fp was Re: G5

[Michael Winter]

On Wednesday, June 25, 2003, at 09:42  PM, Peter Tattersall wrote:

> 	3) even the benchmarks showed that the Mac was still slower than the 
> Dell in integer arithmetic, though it beat the Dell handily in 
> floating point.

Just to clarify, a single 3 GHz P4 or 3.06 GHz Xeon beat a single 2 GHz 
G5, but the dual G5 beat the dual Xeon (P4 can only do one CPU). To me, 
that says something about how well the G5 scales to multiple processors 
(at least two) compared to the Xeon.

> The claim was then made that integer arithmetic is more important than 
> floating point, so this shows the Dell is better. I can't speak to 
> that:

I wish I could find someone who could. My impression was that integer 
used to be much more important, but that it was a side effect of 
processors simply being much faster at integer math than floating 
point. That means many developers coerced their floating point data 
into integer values to improve performance. The simplest example would 
be a checkbook program that represents everything internally in cents 
(integer) and only converts to dollars and cents (floating point) for 
display purposes.

Since floating point speed has caught up and sometimes outstripped 
integer speed, those kinds of hacks are no longer necessary. Which 
really leaves me wondering what the relative importance between fp and 
int really is today. Also, consider this. The G5 has two integer 
execution units and two floating point units. If integer math was so 
overwhelmingly important, why wouldn't they have 3 integer units and 
one floating point?

-Mike