QT7 in Panther

[G5Unit]

I have a G5 1.8Ghz and 1.25Gb ram, Geforce Fx 5200 blah blah...
When I play one of those trailers on apple.com(the 1920 by 1080) I get only about 18 fps. Also when resizing any hd trailer, the fps on Quicktime getting biiger and smaller are pretty low too. Is it because I still have Panther?

 

[G5Unit]

Anyone?

 

[jsw]

It's not Panther - HD video is immensely taxing on the CPU, and I don't think that Tiger will help much. I tried it under Panther, then under Tiger, and I didn't notice a difference - not to say that there isn't a difference, but it certainly isn't huge.