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3/5/01 Monday's News: Story DetailReturn to News Page

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Reader Comments on OS 9 tests with and w/o Altivec Extensions:
Last Updated: 3/5/2001, 9:36 AM
OS 9.-9.04 included 4 Altivec support extensions (noted in the G4 cpu upgrade reviews here). OS 9.1 does not use these and will remove them during the OS upgrade as noted in reports on the OS 9.1 Feedback page here. A reader sent a note on tests in Altivec aware apps with and without the extensions enabled. (Note - many applications that actually support altivec would have that support already installed in the application as part of its compile process. The OS 9-9.04 extensions are beleived to be for other OS use, which in OS 9.1 were included in other core parts of the MacOS, rather than separate extensions.)

" Dear Mike,
Thanks for your very informative site.
You noted in your OS9.1 feedback page that OS 9.1 installation removes the Altivec extensions.
[They are not a part of OS 9.1-Mike]

I have been carrying out some tests over the weekend on my Newer Tech. MaxPowr G4/450 upgraded B&W G3/350 Power Mac, and the conclusion I have reached is that neither OS 9.0.4 or OS 9.1 need the 9.0 Altivec extensions (vBasicOps, vBigNum, vectorOps etc) to have the velocity engine enabled, at least for PhotoShop 6, N2MP3 1.5b3 and for the Newer Technology's Guage Pro v1.2. [Note: GaugePro 1.1 was the last version I saw at newer's web site-Mike]

My configuration is a PowerMac G3/350 B&W (Yosemite rev 1) which has been upgraded with a Newer Tech. G4/450zif, and is running at 450/225 with 1Mb backside cache. 384Mb RAM, upgraded HD (16Gb Maxtor DiamonMax 40) with 2 additional internal IBM Ultrastar 9Gb scsi lvd drives on an Adaptec 29160N interface.

I ran tests with PhotoShop 6 (which had been allocated 293Mb memory) on a 99.6Mb RGB A4 size 600dpi photoshop file, timing a rotate canvas 90 degree CW operation using PhotoShop's internal timing display, ensuring that all disk activity after opening the file had completed before initiating the operation.

On both OS 9.0.4 and OS 9.1, I got the same timings with and without the Altivec system extensions (extracted using TomeViewer from MacOS 9.0). (rotate 90deg cw took approx 1.8/1.9sec).

Removing the PhotoShop Altivec core support plug in (v6.0 which ships with PhotoShop 6) _did_ make a difference (the rotate 90deg. cw took 3.8sec).

In all 4 combinations (OS 9.0.4 & 9.1, with & without 9.0 Altivec system extensions) Newer Tech's Gauge Pro v1.2 reported that Altivec was fully supported. (I have the MaxPowr extension and control panel always installed, but I think this only enables the 1Mb backside cache. The MaxPowr control panel appears defective/inoperable under OS 9.1-- I hope I don't need it in the future.)

And in all 4 combinations N2MP3 v1.5b3 took the same time to encode a 10minute AIFF file from disk to disk. (2'59" to encode the 1st movement of Bach's Brandenberg 4 Philips/English Chamber Orch (duration 9'59") at 128kbps fixed rate Better quality to MP3)

I tried the same operations on MacOS 9.1 with my cpu swapped back to the G3/350, and found speed differences which were more than could be accounted for by the change in CPU clock speed.

Incidentally, iTunes 1.1 seems to be Altivec aware -- under Edit>Preferences on the 'Importing' tab, the settings section displays 'using Velocity' as well as my MP3 encoding settings.
[Since SoundJam MP supported altivec it's not surprising that iTunes does -Mike]

In general, I have had good results on upgrading to OS 9.1. I'm trying to troubleshoot a problem where the machine does not wake up from sleep, but it might mean changing the hard disk driver, which I don't have time to do at the moment. I am using Hard Disk Speed Tools 3.1.1

I hope this will be useful to you and others.
best regards, Sayling Low"

Several readers replied with what I had always suspected - the OS 9.0x Altivec extensions are for OS support of Altivec - applications can have the support embedded via an Altivec aware compiler.

 
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