"
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.
