Powermac G5 powerful enough for HD video?

I can't say for sure since I don't work with HD video but, if you upgrade your RAM to at least 3 GB and use programs meant for PPC it should work ok.

I edited HD video on my PowerBook 1.5ghz 512mb machine and wasn't too hard. It took overnight to render some stuff though. Very possible with what you have now!

My experience of video editing is not great, but I've done a few projects in Final Cut Studio 5.1 which runs fine on my dual 1.8GHz G5 with 2Gb memory and Nvidia Geforce 5200.

I'd be surprised if your system wasn't up to the job, but to play it safe I'd avoid running unnecessary programs in the background - web browsers (Flash advert banners tax your rig more than you know!) iTunes etc.

Basically allocate as much cpu time to iMovie and After Effects as possible and I reckon you should be ok. It will probably take a while to render but should do so nonetheless. As mentioned before though, try and bump your memory up as much as possible.

Hth 😉

I've edited on worse, but not HD. Should be fine though, if not a little slow for some things, like rendering, but that's always the case. Even my Mac Pro takes awhile to import and render, even SD, just the way it is. But yeah, get more RAM.