Blu-ray vs 12x DVD: Read Speed

[Jeremy Charette]

<div class='os_post_top_link'><a href='http://www.gamespot.com/pages/profile/show_blog_entry.php?topic_id=23916169&user=skektek' target='_blank'>http://www.gamespot.com/pages/profile/show_blog_entry.php?topic_id=23916169&user=skektek</a><br /><br /></div><i>"At 2x Blu-ray can read as fast as 12x DVD's minimum read speed. At just 3x Blu-ray is comparable to DVD at 12x; through the first half of the disc 3x Blu-ray is faster, through the second half of the disc 12x DVD is faster. And at only 4x Blu-ray manages to best a 12x DVD's maximum read speed by 9%."</i><br /><br /> <img src="http://www.digitalmediathoughts.com/images/12xdvdvsbdrs0cg.jpg" /> <br /><br />Actually, the statement above is slightly incorrect. Most commercial mastered DVDs read from outside-in, so the first half of the disc would be faster than a 3X blu-ray drive. Why should you care? To save money, Sony will likely spec. a 1X or 2X blu-ray drive for the PS3. Since most DVD games for the Xbox 360 are only using 25-30% of the disc's capacity, all of the game data is on the outer edge of the disc. This means significantly longer load times for the PS3 than the Xbox 360. DVD drives also have quicker search and access times than blu-ray drives. The 360 will not only be able to read data from the game disc faster, it'll also be able to find it faster. Sony has two options: pre-cache disc data on the hard drive (unlikely), or put a 4X drive in it and drive the price even further into the stratosphere.

[Felix Torres]

Pre-cacheing on the HD is indeed unlikely 'cause the baseline PS3 will come minus HD. (Whenever it actually ships...)
It is slated to be an extra-cost option, just like on the PS2.

Interesting comparison, though.
Basically BD-ROM adds cost to the PS3 and does nothing to enhance gameplay. MS has gotta love that.

Odds we won't see BD-ROM on the PS3 just went up another bit...

[vission]

I was wondering where it is you found this information?

"Most commercial mastered DVDs read from outside-in"

To the best of my knowledge both commercial/non-commercial CD/DVD's are always read from and written to Inside-Out.

[Jeremy Charette]

Commercial pressed DVDs can be made however the manufacturer wants, that is, they can read from inside out or outside in. For instance, most dual-layer movie DVDs read from inside out for the first layer, and outside in for the second layer. This way the tracking motor doesn't have to transition all the way from the outer edge of the disc to the inner edge at the start of the second layer, causing a delay in data output (recognizable to the viewer as a pause in the movie between layers).

Xbox discs use a proprietary file system which reads data from the outside in, as does the 360.

[Doug Johnson]

It is the second layer of DVDs that can be outside-in or inside-out. The first layer is always inside-out.

[Doug Johnson]

Xbox discs use a proprietary file system which reads data from the outside in, as does the 360.
This is not correct. They do have proprietary formats, and they may read outside in on the 2nd layer, but the 1st layer is inside-out, just like other DVDs. (Look at your game discs... data on the inside, not the outside.)

[Jeremy Charette]

Well, I've searched and can't find a definitive answer on this. If someone can point me to it, please do. I suspect Doug's answer is probably the correct one.

Regardless of whether data is inside out or outside in, the end result is the same: a 12X DVD drive is faster than a 1X or 2X blu-ray drive when it comes to data transfer rates and access times. Advantage: 360.

Unless of course Sony decides to make the PS3 blu-ray drive backwards compatible with the DVD format, and produce games using DVD discs rather than blu-ray discs. This is one possibility I wouldn't rule out just yet. PS3 game developers have admitted that they are designing their games for 10X DVD drive capabilities (http://games.kikizo.com/news/200602/065_p1.asp). What exactly this means is anyone's guess.

"PS3 isn't going to have writing capabilities and for us that's of no concern right now. Our stuff runs off a Hard Disc at the moment and won't exceed DVD capabilities; we're programming the game as if it will be written for a 10-speed DVD drive. Anything less would affect load time."