Does DMA enabled/disabled affects the writing speed?

Hey :smiley:

I know that enabling DMA with a CD-ROM drive makes reading of a CD faster.

But does it have any effect on the writing speed of a cd-writer, too? :confused:
Is the writing speed limited when DMA is disabled :confused:

absolutly. I couldn’t get above about 19x when dma was off. So if you want to take advantage of the speediest burners, dma needs to be on. It also applies to dvd drives, hard drives, dvd burners, etc.

DMA affects the CPU utilization, keeping it at a low level as the CPU is bypassed when memory is accessed. When CPU utilization is minimal, the full speed capability of a drive can be realized.

If DMA is not enabled, the CPU loads up and prevents the full speed capability of a high speed drive. Typically, in this case the drive is forced to switch to a lower speed mode of operation than the maximum speed performance specification.

Thanx a lot for these detailed information :slight_smile:

So I could burn only 16x with the BurnMax32 using 48x media.

But after enabling DMA, the computer totally freezes every time :frowning:
when starting NTI CD-Maker 5.1.17 :confused:
Without DMA everything works fine, except of the low speed (16x)

Is such a problem usually related to the CD-RW drive or the CD-software :confused:

Configuration of my “test computer”:
Windows98SE
AMD K6-450
256 MB SDRAM
Polaroid BurnMax32 (=BTC BCE3212IM)
NTI CD-Maker Professional 2000 v5.1.17
Core 48x media, Moser Baer India

DMA problems are often caused by chipset/motherboard issues. I have no investigated it thoroughly but have seen this on a few low-end systems. Some computer just can’t function properly with DMA on no matter what you try.

DMA has nothing to do with burning software, and is related to the burner and motherboard support.

BTC does not list the connection mode in their BCE 3212IMproduct specs to show if DMA is supported. This is unacceptable. I know of no other manufacture that leaves this out.

According to this Review, the drive reads the media speed and won’t exceed the rating of the disc.

There are several possibilties for your problem:

  1. The drive doesn’t support DMA. This is not likely, as DMA support is virtually universal for new drives and drives of this speed rating.

  2. The drive is reading your 48x media as only 16x capable and won’t allow it to burn at a faster speed. This is also unlikely.

  3. DMA is not properly implemented. This is the most likely cause of the problem. Using the latest busmastering or chipset drivers will sometimes fix a DMA problem.

Wow, I never thought that I would get so many helpful information :slight_smile:
This forum is really great !! :smiley:

Okay,
I just finished some testing and have narrowed down the problem to the motherboard.

First I verified in the Bios that DMA is enabled/supported.
Enabling DMA with a TEAC CD-RW caused the same problems :frowning:
So it’s not the Polaroid cd-writer :slight_smile:

As you may have noticed, my “test computer” doesn’t have the latest hardware installed (it’s mainly for software testing) and the ALI chipset drivers are still the original ones from 1998/99 :confused:

I will try to find new chipset drivers for the motherboard now :wink:

[i][B]Originally posted by Inertia

  1. The drive doesn’t support DMA. This is not likely, as DMA support is virtually universal for new drives and drives of this speed rating.[/i][/B]

Isn’t that impossible? PIO4 is 16.6MB/sec so DMA is really the only option for greater transfer rates I believe.

:smiley: :smiley: :smiley: :smiley:

Thank you very much, Inertia and 83bj60 - problem solved :bigsmile:

I updated the IDE-driver of the ALI motherboard and
… no problems at all with DMA enabled.

Now I can run some tests with the Polaroid BurnMax32 at full speed.
My first impression of the drive is very positive.
Now on sale for only €50 (=US$50) :wink:

FYI: The Polaroid BurnMax32/BTC BCE3212IM does support DMA.

hey guys, help me out. I’m running Winxp pro.

my lite-on 40x lags my computer like a mofo when it reads from cd’s. But my Artec DVDrom doesn’t lag the pc at all.

winxp enables dma mode by default… for dma capable hardware on the ide channels.

But i never understood why reading a CD from the burner drive lagged my comp so much.

Originally posted by BadReligionPR
[B]

Isn’t that impossible? PIO4 is 16.6MB/sec so DMA is really the only option for greater transfer rates I believe. [/B]

If you will read my earlier thread, you will see that the bottleneck in burner speed is in CPU utilization, not throughput speed. The “cooked” ISO data throughput of a 1x drive is 150 KB/sec., raw is about 172 KB/sec. A 32x drive requires only 5.5 MB/sec, a 48x drive requires about 8.3 MB/sec, and a 56x drive requires about 9.6 MB/sec of bandwidth capability (raw data).

The most important feature of higher connection speeds for burners is the advanced DMA modes, not the throughput speeds. The highest throughput speeds are available only for buffer “bursts” from the burner, which won’t be noticable in normal use. For example, for a burner with a 2 MB buffer and an ATA 33 (UDMA 33) connection, the buffer burst will be done in 60 milliseconds.

The importance of DMA is also demonstrated in the noticeable performance difference between PIO mode 4 and DMA Multiword Mode 2. Both of these protocols have a transfer rate of 16.6 MB/sec, but a fast drive operating in PIO 4 will typically not reach its top performance as it will with DMA Multiword Mode 2.

Well, it’s always gratifying when problems get solved and when users actually post their results for all to benefit, helps all future users with similar problems :slight_smile:

I did try the driver update on my mother in law’s machine when I got my Plexy 1210A from the US while visiting there two years ago (wanted to see if the drive was working, hehe). No luck there. Mind you, she had a fairly weird MOBO setup forget what it was (Yes I know, I forget a lot - wait till you reach my age… Anyway it was running a Cyrix CPU!). Just couldn’t get it to work (blue screen and hangs). But hey, at least I could browse all my fill on her broadband connection :slight_smile: and got to make a successful test burn anyway.