BUFFER OVERRUN on an iMac G5 1.6GHz 256MB

[NoisyCricket]

I almost couldn't believe my eyes. iMac G5 1.6GHz 256MB. Sales guy was burning a data cd for me (captured some movie clips using iMovie ), and then while system was burning, he was showing some other features of the iMac when the message came out.. BUFFER OVERRUN.

And I thought those things were things of the past..

Is this normal?

Di naman kaya pinalitan ng dealer ang orig na combo drive? It was a Matsuhita or something like that cd-writer.. 56x yata.

[Henjie]

Originally posted by NoisyCricket
I almost couldn't believe my eyes. iMac G5 1.6GHz 256MB. Sales guy was burning a data cd for me (captured some movie clips using iMovie ), and then while system was burning, he was showing some other features of the iMac when the message came out.. BUFFER OVERRUN.

And I thought those things were things of the past..

Is this normal?

Di naman kaya pinalitan ng dealer ang orig na combo drive? It was a Matsuhita or something like that cd-writer.. 56x yata.

The combo drive used in the iMac G5 can only burn CD-Rs at a max of 24x. IMHO, the dealer won't gain much by replacing the stock combo drive with a third-party unit since 1) Apple already uses some of the slowest and cheapest combo drives out there, and 2) replacement slot-load combo drives are not that easy to find. Besides, replacing it with a slower drive will actually decrease the chance of buffer overruns since slower write speed = lower hard drive throughput required. :-) And no such thing as a 56x CD-RW drive. Fastest right now is 52x.

If his demos involved a lot of hard drive access, then that could be the reason. Burning at 24x, the combo drive needs to receive data at a constant 3600KBps. Interrupt the flow of data and you've got a coaster. The drive does have a 2MB buffer but that's barely enough for half a second of burning. I reckon the hard drive is also heavily fragmented since 3600KBps is practically nothing when we're talking about modern hard drives.


~Henjie

[vicicasas]

What was the dealer using to burn? The built-in burning capabilities of the OS or a third party app like Toast?

Agree with Henj on Apple using the slowest and cheapest drives compared to equivalent PC systems. Even for a plain old combo drive, it's ludicrous how crippled our beloved Macs are at burning CD-Rs when compared to a garden variety box from any old PC store.

[Kenneth]

Yup, this is normal. Even with PCs. Once, while burning on my 1.6GHz Athlon with 1 gig of memory, I mere used IE to surf a website, then I think it loaded a cpu intensive flash movie. Ayun, coaster city. That's why when I burn, I make sure that its the only thing running, or that the other apps don't use much of the cpu or HD.

[NoisyCricket]

Ah. Weird. Application used: Toast 6 Titanium. When the disc became a coaster, we were only running one other "app".. Actually it was the "System Info" thingie under the Apple Logo (i think). Nothing else was running. Just Toast and "System info". iMovie was closed and not capturing any video at the time.

There were some burning options. "Best" whatever that meant.. and then 1x all the way to, yes, 56x speed. Since we had to burn three disks, I used "Best" on the first one (which became a semi coaster..) 48x in the 2nd one, and 56x on the third one.

(Pero baka naman the cd-r could only support 48x.. who knows).

The process would take anywhere between 5-7 minutes although it felt much longer.

At the end, it would prompt to say: (V)erify and (M)ount.

What is mount?

[Henjie]

Originally posted by NoisyCricket
There were some burning options. "Best" whatever that meant.. and then 1x all the way to, yes, 56x speed. Since we had to burn three disks, I used "Best" on the first one (which became a semi coaster..) 48x in the 2nd one, and 56x on the third one.

(Pero baka naman the cd-r could only support 48x.. who knows).

For the iMac G5's combo drive, "Best" will be 24x. The 48x and 56x options are only there in case you have a 48x or 52x burner. The usable/supported speeds (dependent on the drive you're using) will be in bold, and are the only ones you're supposed to use. ;-)

The process would take anywhere between 5-7 minutes although it felt much longer.

Yup, 5-7 minutes or longer = 24x or slower. Burning at 48x or 52x will take less than 3 minutes (not including verification).

At the end, it would prompt to say: (V)erify and (M)ount.

What is mount?

Mount means just that, mounting the CD on the desktop. :-)


~Henjie

[NoisyCricket]

Ah, thanks man. All the speeds seemed to be of the same font size and shape.

I hope the superdrive performs better!

[Henjie]

Originally posted by NoisyCricket
Ah, thanks man. All the speeds seemed to be of the same font size and shape.

I hope the superdrive performs better!

The iMac G5's SuperDrive is actually slower when burning CDs (16x max). But then again, slower CD burning speed = less chance of buffer errors. ;-)


~Henjie