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Re: IDL time test with a PowerMac G4 [message #17334 is a reply to message #17330]

Fri, 08 October 1999 00:00

pford1955
Messages: 2
Registered: October 1999

Junior Member

In article <b13L3.5294
$cPf.197315584@news.telia.no>,
roy.hansen@triad.no (Roy E. Hansen) wrote:
> In article <gurman-
0410991751060001@barkochba.nascom.nasa.gov>,
> gurman@gsfc.nasa.gov (Joseph B. Gurman) wrote:
>
>> Running IDL 5.2 without any special
Velocity Engine (AltiVec) plugins
>> or other mods, a G4/450 running Mac OS 8.6
with 128 Mbyte of memory and a
>> 20 Gbyte Western Digital (stock) Ultra ATA
hard drive gets the following
>> results on time_test2:
>>
> snip - snip
>
>> 4.73333=Total Time,
0.096772401=Geometric mean, 23 tests.
>
> Running time_test2 on my P-II 400 laptop
produces the same total time
> (4.7300 seconds, see below). I though the new
G4 was a > 1 Gflops machine
> excellent for numerical stuff but, this small
comparison indicates that my standard
> PC is equally fast.... Is there something I am
missing here, or is'nt the new G4 as
> fantastic as announced? Well, to answer my
self - I fooled myself by studying the total
> time from time_test2. By studying test 20 in
time_test2 (forward and inverse 1D FFT)
> the test looks like this:
>
> G4/450: 20 0.150000 131072 point
forward plus inverse FFT
> G3/350: 20 0.300000 131072 point
forward plus inverse FFT
> Alpha500: 20 0.243165 131072 point
forward plus inverse FFT
> P-II 400: 20 0.550000 131072 point
forward plus inverse FFT
>
> So it may be that the G4 is a supercomputer
after all.....
>
> --RoyH
>

Roy, yes you did miss something. As stated in the
introduction to the test: "without any special
Velocity Engine (AltiVec) plugins or other
mods..." The Gflop range applies only to AltiVec
instructions. Your results are like saying MMX is
no good because my application, which doesn't use
them, shows no improvement in graphics. The G4 is
only marginally faster than the G3 in floating
point math without AltiVec. Both are faster than
a Pentium series at the SAME CLOCK SPEED, but
Pentium are clocked higher! While IDL is going to
support AltiVec, I don't believe it is the case
here. Now if you want to dump on Apple for slow
disk drives and slower graphics, you might have a
point. (I'm not so sure about the graphics now
days, I believe it on par with Wintel machines.

Regards

Patrick Ford, MD
Baylor College of Medicine
pford@bcm.tmc.edu

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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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