A purportedly leaked Intel memo explains why Apple's processor partner has decided to lend its weight to the HD-DVD standard.

The revelation emerges as a wave of HD announcements strike, with Sky launching an HD service that includes free broadband access, and Disney company Buena Vista revealing plans to launch its first batch of movies in the competing Blu-ray format.

Blu-ray and HD-DVD are two competing standards that aim to become the replacement for existing DVD releases.

The Intel memo - revealed on the AVS Forum - may not be genuine, but does point to three reasons why HD-DVD will prevail. Apple supports the Blu-ray standard, but is expected to remain technology-agnostic until it becomes clearer which standard will win.

According to the memo, HD-DVD is superior because it is the one that's most compatible with current DVDs. This means its easier to re-jig existing production lines to manufacture HD-DVD discs, meaning Blu-ray discs may be up to 35 per cent pricier.

The memo also notes that while Blu-ray offers higher capacities, both formats can support HD video, meaning the cheaper format may win the race for the next-gen DVD space.

The memo is available here.