lol my apologies too for sounding like an arrogant twit although it is true what was posted.

@ Guiding Light

Thx for your info, this topic has been long debated and it seems like there's been a lot of misinformation and conflicting sources regarding read speed/seek time comparisons.

I don't mean to be cynical but there's a couple of concerns that I don't understand and maybe if I can 'pick your brains' now we can put the issue to bed once and for all.

1. After being force fed the quote from beyond3d for so long - I was wondering if you could help me understand how exactly the 360 reads DL at the same speed as SL?

2. Is the read speed then the quoted SL speed or something else? - "12x DVD-Rom Drive SL (9.25MB/S-15.85MB/s(AVG ~8x(10.57MB/s)" (obviously that average doesn't account for optimisation).

Pretty simple really...

12x is it's official maximum speed when reading a dual layer disc. It would only reach this speed when reading data on the very outer edge of the disc. So, since the outer 1GB (roughly) is never used it would reach a maximum speed of (educated guess) 11.1\11.2x (note I haven't done an actual sum to achive this because the CAV doesn't increase\decrease reading speed at a linear amount.

So...roughly speaking...

Starts reading the inner ring at around 5x -> 11x (then changes to the 2nd layer and reads backwards).

If you read the disc with a tool like Nero CD-DVD speed, the speed would appear as an "arc"...

Most Xbox 360 games are around 5GB, this game data is placed after the dummy\padding data, also to further optimise, movies\fmv are placed straight after the dummy\padding...Stuff that needs to go with a "now loading" screen is placed as far away from the centre as possible...

This is why games like Soul Calibur 4, Street Fighter 4 etc have very similar loading times to the PS3 even though the PS3 has an install. You see, quoting the average read speed for the Xbox 360 is very misleading due to the CAV reading, do people really think the developers are so stupid that they would place data that needs to be read as quickly as possible closer to the inner ring of the disc (rhetorical question).

To add to this, you will see that raw game assets (excluding movies) don't actually take up that much space so for games that are 6.8GB (maximum). They normally have a lot of movie data which would be placed in the centre.

Not sure if it needs to be said, but the movie data read speed doesn't matter since it only needs to be read fast enough to not skip. A DVD running at 3.3x is fast enough to display 1080p bluray at highest quality possible.

....Oh to answer your actual 2. question, the answer is yes. However you have to take into account that the last 1GB isn't used on the disc so it will take the average down a little I have no exact number, but you could easily test this yourself by burning a DL DVD-\+R with 7GB of data, then using Nero CD-DVD speed to produce a graph setting the maximum read speed to 12x. Most DVD-ROM pc drives these days read at 12x for DL media. (12x reached at outer edge)

Why would the outer edge data not be used? DVD players read from the inner track outwards and the data they put there so they can fit within DVD specifications and show that movie (You have put your disc in something that isn't an Xbox 360, idiot). So the outer track is definately being used.

Outer track? No such thing, there's two tracks\layers one on top of the other.

The Xbox 360 DVD isn't a "normal" DVD-ROM of a DVD-Video, it is a hybrid of the two with some extra proprietory "standards". Think of it as a CD+G type CD. Which can have CDDA audio for your CD player and a CD data partition on the same disc\layer.

What you say is the logical answer...But it's not actually true for some bizzare reason MS do not use the outer 1GB (well 500mb since it takes 500mb from each layer). Just look at a normal Xbox 360 disc and it's easy to see for yourself and you can see where the data stops.

Just to clarify, as far as I understand this brings up 3 possible options;

1. DVD drives read dual-layer discs at the same speed as single layer.

2. Microsoft (rather bizarrely) have been quoting the slower DL maximum read speeds (12x) and the single layer then must read at 16x???

3. The 360's dvd drive is special and only it reads DL discs the same as SL because....<fill this space>.

;_;

There must be a logical reason for that then.Though my dreams of Xbox 360 hedgemony have been shattered.

@Fumanchu they could be quoting an average speed?

Who knows I guess the most likely answer is that ALL games use the DVD-9 format regardless of size and it would be deliberate misinformation for them to quote the SL maximum speed if never used.

Could be, I always see it listed as a 12x DL drive. I never see single layer speeds spelled out.

That is kind of weird though as most marketing teams would list the highest possible number achieved - if you were to buy a PC DVD-ROM the big number taking up 90% of the box real estate is the SL maximum read speed.