imac g5 does it have dual layer dvd burner?

i just recently bought a imac g5 17 w/screen after my pc harddrive took a crap. I just had it with windows and pc. The last apple that i had was a black and white macintosh that used floppy to run. But anyways...i was wondering does this imac have a dual layer dvd burner? Also if i use idvd to make a slideshow and if i burn that slideshow onto a dual layer dvd will idvd use less compression allowing more quality to my project. Just wondering because i feel that my slideshows don't look as good as i want them to be. Maybe its just me. oooh also i have another problem i have the oem keyboard with usb at the top of the keyboard. When i plug in my pny usb memory stick it gives me a usb low power. But if i remove one one usb devices it still gives me the same error. But if i plug in my pny stick to the back of the imac it works fine. any ideas? any help would be greatly appreciated. thanks in advance.

A) Should be dual-layer.

B) I'm presuming "low power" means USB 1.1 speeds? The one's on the Apple keyboard are USB 1.1, not USB 2.0.