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Why does the read speed take so long to reach max?

Posted: Thu Aug 22, 2013 4:40 pm
by brandont
Basically my question is the subject - my drive is fine as the read speed EVENTUALLY gets up to around 10x. However it starts at less than 1 and slowly creeps up to 9+ with most discs. I've probably seen as high as 10.5 or 11x. Is there any reason for this and can I tell it to start trying the disc at 8 or something? I tried upgrading the firmware and poking around in the device settings to no avail.

Drive is an Asus BC-12B1ST, Windows 7 x64, 8GB Ram, I5-3550, 7200 RPM SATA Drive. Not really taxing CPU, RAM, or HD at all.

Re: Why does the read speed take so long to reach max?

Posted: Thu Aug 22, 2013 11:05 pm
by joe42
That is how optical drives work. The throughput is higher on the outer parts of the disc.

Re: Why does the read speed take so long to reach max?

Posted: Fri Aug 23, 2013 6:26 pm
by brandont
Ok, that can explain part of it, but I also clearly hear my drive speeding up as the copy progresses...? It starts off almost silent and gets very loud in maybe 3-4 steps. Also on some discs it is silent the whole time but the speed only gets up to 4-5x on those.

Re: Why does the read speed take so long to reach max?

Posted: Fri Aug 23, 2013 10:44 pm
by joe42
Most drives can read single-layer blu-rays faster than dual-layer blu-rays (by spinning faster), so you will probably hear more noise from SL than DL.

But most of the changes you hear are probably just PCAV changing the rotation speed at various portions of the disc.

Here is a decent explanation of the various optical drive rotation techniques:

http://www.hughsnews.ca/faqs/authoritat ... -speed#8.2

Re: Why does the read speed take so long to reach max?

Posted: Sat Aug 24, 2013 5:02 am
by joe42
If the drive is running in CLV or PCAV mode, it will change speeds at various portions of the disc.

Go here for more explanation, change the [dot] to .

www[dot]hughsnews[dot]ca/faqs/authoritative-blu-ray-disc-bd-faq/8-recording-and-reading-speed#8.2

Re: Why does the read speed take so long to reach max?

Posted: Sat Aug 24, 2013 5:01 pm
by doncht
However it starts at less than 1 and slowly creeps up to 9+ with most discs.
That is a standard. I mean, it slowly increases the speed and see if it would produce errors. Until it would reach the maximum potential speed.

Re: Why does the read speed take so long to reach max?

Posted: Sun Aug 25, 2013 12:24 pm
by joe42
doncht wrote:I mean, it slowly increases the speed and see if it would produce errors. Until it would reach the maximum potential speed.
That is not true. With every optical drive I have done a rip with, it starts at the maximum speed it is capable of (for the current portion of the disc), and only reduces the speed below the maximum possible if it has errors or difficulties reading.

Re: Why does the read speed take so long to reach max?

Posted: Tue Sep 10, 2013 7:42 am
by angelgraves13
10X is a great speed for optical drives, if you're talking about DL BDs. Pioneer's drives are locked at 2X, and LG drives hit 8X (10X unlocked).