| Re: Impressions of IDL on PowerMac vs. Sparc [message #3630 is a reply to message #3535] |
Thu, 09 February 1995 11:05  |
gurman
Messages: 82
Registered: August 1992
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Member |
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In article <walsteyn.791758364@ruund3.fys.ruu.nl>, walsteyn@fys.ruu.nl
(Fred Walsteijn) wrote:
> In <Pine.CVX.3.90.950131111953.24952A-100000@sstcx1.lanl.gov> Jeff Bloch
<jbloch@sstcx1.lanl.gov> writes:
>
>
>> We have just started playing with IDL on a Power Mac (Quadra 650 with Power
>> Mac upgrade card, (6100/66 equivalent) with 40MB of memory) and comparing it
>> to IDL running on a Sparc LX. We have found some very interesting speed
>> differences. Simple large array operations are a factor of two FASTER on the
>> Power Mac than on the Sparc, yet transcendental function array operations
>> (sin, asin, tan, etc) appear to be a factor of two SLOWER on the Power Mac.
>
> You might get a higher speed on the PowerMac if you would install
> a new floating point math library (made by Apple). It's called MathLib.
> Ask or read about it in a comp.sys.mac.* newsgroup. (I don't know the
> details as I don't have a PowerMac. The only thing I do know is that
> the MathLib in ROM is ``slow'' when it comes to transcendental functions...
> The software patch, i.e., the MathLib extension, solves the speed problem.)
>
> Good luck,
> Fred. (walsteyn@fys.ruu.nl)
Another determinant of speed in math-dependant operations on PowerMacs
is the presence (and size) of level 2 cache. Does the Apple upgrade card
come with an L2 cache card?
Joe Gurman
--
J.B. Gurman / Solar Physics Branch/ NASA Goddard Space Flight Center/
Greenbelt MD 20771 USA / gurman@uvsp.gsfc.nasa.gov
| Federal employees are still prohibited from holding opinions while|
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