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Re: IDL time test with a PowerMac G4 [message #17330]

Fri, 08 October 1999 00:00

gurman
Messages: 82
Registered: August 1992

Member

>> ...
>> Since the G4's beat Pentiums runnjing Windoze hands-down in IDL
>> ...
Sorry, that remark referred to the demo of a not-yet released version of IDL
with optimization for the AltiVec ("Velocity Engine") features. I didn't
mean to suggest
that the results in that file were all that spectacular; really, rather,
the reverse.

(In fact, the disk write is the only real loser for the G4 --- without it,
the time total is 3.0 s for the G4 vs. 3.8 s for the PIII.)

You'll note that the geometric mean for the G4/450 is about 20% less
(0.096 vs 0.119) than for the PIII 400, slightly better than one would
expect from the clock speed ratio, but I'm willing to bet that difference
would be recovered if you were running Linux. The difference is that the
Mac OS achieves essentially the same speed on the G4 as any other OS,
since all the math functions are likely to be "native" now. I suspect the
disk I/O is still partly 68K code, thus the pokeyness.

>
> The PC is faster overall, though some of the floating-point intensive
> operations are slower (e.g. 9, 20). Hardly "hands down".

Wait 'til January (when, of course, there will be 700 MHz PIII's, 750
MHz K-7's, and at least samples of 1.3 GHz Alphas). I suspect the
AltiVec-optimized IDL will pull some numbers way down.

Joe Gurman

--
Joseph B. Gurman / NASA Goddard Space Flight Center / Solar Physics Branch /
Greenbelt MD 20771 / work: gurman@gsfc.nasa.gov /other: gurman@ari.net

Government employees are still not allowed to hold opinions while at work,
so any opinions expressed herein must be someone else's.

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[Message index]

		Re: IDL time test with a PowerMac G4 By: gurman on Fri, 08 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: Patrick V. Ford on Fri, 08 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: pford1955 on Fri, 08 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: pford1955 on Fri, 08 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: Mark Hadfield on Fri, 08 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: Pavel Romashkin on Thu, 07 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: roy.hansen on Thu, 07 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: gurman on Thu, 07 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: mgs on Wed, 06 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: Pavel Romashkin on Wed, 06 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: m218003 on Wed, 06 October 1999 00:00
		Re: IDL time test with a PowerMac G4 By: Pavel Romashkin on Tue, 05 October 1999 00:00

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