iMovie encoding differences between PPC/Intel

[dolphin842]

Hi all,

Perhaps this may or may not be already known in the greater Mac community, but I have a suspicion that Quicktime encoding in iMovie on intel is significantly slower than its PPC counterpart.

I did some unscientific tests with my core duo iMac (1.8GHz, early 2006) and a dual 2.5GHz G5 in the school lab. I encoded a 4:13 DV movie with the following settings: 1000kbps, mpeg4 (standard, not h264), QVGA resolution. I clocked the time it took for each machine to encode and used Activity Monitor to observe the CPU percentage each machine was using along the way.

PPC: With iMovie using 55-60% (I assume that's of one core, the figure that's in the process list?), or about 1.3 GHz, it took just over 2 minutes

Intel: With iMovie using 80-100% of one core (1.44-1.8 GHz), the encode took 4 minutes and 40 seconds.

I'd call shenanigans, but before I do, I'd like to see if other people have gotten similar discrepancies between PPC and Intel procs when exporting from iMovie. Anyone else have stories to tell?

 

[theBB]

How much RAM does each one have? Any other apps running in the background, especially for intel version? Anything that requires Rosetta such as MS Word?

 

[dolphin842]

The G5 has 2 GB, the iMac has 1.5 GB... no taxing or Rosetta-requiring apps going on in the background for the iMac. When not encoding, both of the iMac's cores were around 98-99% idle.

 

[bankshot]

Interesting! I recall feeling a bit disappointed some time ago that a particular encode wasn't as fast as I thought it would be on my 2.0 original Macbook, as compared to my 733 MHz G4 tower. Then again, it took a few hours on the G4, so even getting down to an hour or hour and a half on the Macbook would still have "felt" slow.

Maybe I'll do a more carefully measured test now and see what happens. I have to admit I'm kind of curious now.