16x burn actually burns at 5x



I’m having issues with my internal NEC 3550A and LG GSA-H10N. I’ve updated the firmware for each to the most currrent (from cdfreaks firmware, JL11 for the LG, and MAD DOG MD 1.F2 for the NEC). But at 16x burn, I’m only getting up to 8x on the first 35 sec of burning then starts to drop down and settle at about 5x. I’ve used Maxell, Fuji, Imation, Sony, and Philips 16x media. And all are testing at that speed.

I’ve tested the burn speed on these drives using Toast 8, and MBBench (Mac). My older Mac G4 had the same NEC 3550A, and it burned at a much faster rate. That’s how I first noticed the slower speed on these drives.

Using Toast to test time on burning. On the older G4 it would take about 3.5 - 4 min to burn a full 4GB DVD at 16x. The burners on my new G4 says it will take about 4 min, but actually takes about 10 min.

But ripping a full 4GB DVD, burning CD-R at 48x, and reading DVDs is all within normal parameters. And I don’t think I’ve ever had a bad burn (maybe one) under “16x” burn option.


Clearly, the source delivers the data TOO SLOW.


Can you explain why this is happening? Can a nicked IDE cable cause this? Or would the culprit be the PIO/DMA setting?

I forgot to include this bit of info, but I thought it might help: With any of the DVD-R media I’ve used, at random times when I insert a DVD-R disc, they weren’t recognized. Either Toast will not launch automatically, or it’s telling me there is “no disc inserted”. I would have to eject a couple of times before the disc is recognized. This happens on both drives. Which seems too coincidental for me to believe it’s the hardware itself that’s faulty.


I’d suspect DMA/PIO , a damaged IDE cable or incorrectly jumpered devices if it were on a Windows PC so presumably the same applies on a Mac.

The 8x speed you see will be during the lead-in where all the Windows burning apps show the selected speed rather than the actual speed.


FYI, JL12 is the latest FW for the H10N.

Either drive will automatically lower burn speeds for the duration of the burn, if there is a buffer under-run. Software only sets the initial burn speed, after that it’s all up to the hardware.


Thanks CDan, didn’t realize they came out with a new firmware for the H10N already. I just updated it about 2 months ago. Mind you, the drives seemed slower (than what I was used to) right off the bat.

So even if I have Toast (or whatever burning software) set to 16x burn, because of the buffer under-run it will burn slower? This does make sense, but not sure about dropping to more than half the selected speed. I would assume that it would probably drop down to 12x from 16x. Not 5x. Unless I’m very misinformed, and this is a normal thing. But if it is normal, why did the same drive burn much faster on my older G4?

As well, as per Tim’s input, I’ll check the DMA/PIO setting first. If the drives are already set to DMA, I’ll have to replace the IDE cable. I might as well update the firmware again with the latest. I’ll post results.



Software can only read the available speed setting from the drive’s firmware, and offer them to you as an initial speed setting. Once the burn starts, speed is entirely controlled by the drive itself. Possible causes for a drive to downshift during a burn are buffer under-run and low burn quality. Your software should have a readout of the read buffer level and/or drive buffer level that you can observe during the burn. What these 2 buffers are doing will answer the question of whether it’s a buffer under-run issue. Every drive has different parameters as to what it does when it encounters a buffer under-run. Some will downshift to 4x, some to 6x, etc. Some will handle repeated under-runs by downshifting still further.