[iTunes] iTunes Speed/Performance Feedback

[Kunga]

Just sent this to the iTunes team. Thought you would all like to know 
this, if you don't already.

I'm using OS 10.2.6. Ripping AAC files @ 192kbps.

Dual processors DO NOT help increase ripping speed. iTunes rips faster 
with one fast processor than it does with two slower ones that add up 
to more than the speed of the single one. I found that out the hard way.

Bought a dual 867 thinking I was going to get rips more than 3 times 
the 8x I get on my old G4 500 Cube (100 bus). Get no more than 13.5x 
even with the same 52x reader. Both processors are working (can tell 
via Cee Pee You). But they only total the work of one processor and the 
system overhead makes even that not as fast as it would do with one 867 
processor.

So for ripping AAC or MP3 files, it's all about a fast single processor 
with a fast reader so far. Please try to develop a version of iTunes 
that will use the full capability of both processors continually. When 
I do an 8x rip on my G4 500 with a 52x FW reader, the processor is 
working at a full 97%-99% load the entire rip. When I do the same rip 
on my dual 867, both processors are flipping all over the map between 
20% and 80% both totaling little more than 100% at any moment and 
yeilding a measly maximum 13.5x rip speed.

I feel like I got ripped off buying this dual 867 for ripping because 
iTunes is not really a dual processor program thus far. There is 
something wrong with the code that prevents it from using both 
processors up to their full capacity. If you will please fix that code, 
I believe I will be able to get almost 28x rips on this dual 867 which 
would be the logical multiple from my single 500 to a dual 867 or 1734 
GHz or 3.47 times 8 (3.47 is the multiple of 500 that my 1734 adds up 
to).

Is the fact that iTunes doesn't use both processors fully OS X's fault 
or iTunes' fault? Either way, I wish you would make this capability a 
priority in the next version. I have over 3,000 CDs I must rip and the 
process is still way too slow for me to want to do it thus far. I am 
extremely upset to discover this weakness in iTunes which I thought was 
a multiprocessor application. While it uses both processors, it does 
not do so in a way that totals more than the power of one of them. My 
dual 867 is ripping at a multiple of one 867 compared to one 500 (on a 
slower buss too). (500 + 367/500) 1.73 times 8 is 14. All my dual 867 
rips occur at a maximum of 13.5x NEVER 14x. I understand system 
overhead. But on a faster bus from the same 52x reader? Your team 
should really be concerned about this. I would expect a dual 1.8 GH 970 
PowerMac to deliver an iTunes ripping speed of at least the 52x reading 
speed - about 1.1 minute per one hour album or the speed of the 52x 
reader. The bottleneck should consistently be the processors until the 
speed of the reader is reached. Please try to deliver that.

Sincerely yours since SoundJam 2.5.

Kunga