Black Screen with LiveDVD, running on LIveUSB is a work around

A strange work around. For some reason I boot to a black screen with a LiveDVD. Using the DVD on another machine I created a LiveUSB and after another try on the problem machine, the boot issue has disappeared (only with usb boot). Is this perhaps some strange IRQ issue?

Not to frustrate those wishing to boot via DVD rather than USB, it should be mentioned that the age old boot code "acpi=off" still works like a charm on LiveDVD/CD.

It is just interesting that this is not required via LiveUSB.