Quicktime performance Tiger vs Leopard

[huntercr]

OK... I'm not a conspiracy theorist by any stretch of the imagination, but I've had a chain of events that leave me wondering what's going on:

First let me tell you my system: Dual G5 1.8GHz 3.5GB RAM.

Last year I could download and watch 1080i HD quicktime videos ( trailers from Apple's site ) without problems, playing at full resolution with no noticable frame dropping.

Then after a quicktime update ( don't remember which ), the performance fell down horribly to just a few frames a second for HD movies ( lower res videos still played fine ).
The next quicktime bumped up the performance back to something reasonable where I could at least "kind of" watch an HD trailer, but still there were sluggish points on most videos.

So last week I finally pony up for Leopard. Now I can watch 1080i trailers again without any problems and not a single frame drop that I notice.

What the heck??? Is this because of Leopard supposedly offloading some of the work to the video card? I think I read that it does that right?

I have actually noticed better performance all around with Leopard but most obvious is the graphics performance ( minimizing windows, dashboard, webpages etc ). I was mad at myself for not upgrading sooner!

 

[wrldwzrd89]

Leopard did make some changes to the graphics subsystem in Mac OS X, which are responsible for most of the performance improvements you've noticed. My understanding is that QuickTime itself doesn't offload rendering to the GPU, but Core Graphics, which handles things behind the scenes, DOES in Leopard, and didn't do so in Tiger.

 

[Catfish_Man]

CG doesn't offload to the GPU unless it's explicitly enabled in the app. I would suspect this is just due to optimizations in Leopard. As to what caused the slowdown in the first place... no idea :/