DMA mode #s

[TimmyJ]

What do the DMA mode numbers represent? I have sussed that mode 6 is ATA133, but what about mode 2?

 

[lhgpoobaa]

Well it goes like this:

UDMA 6 = ATA133
UDMA 5 = ATA100
UDMA 4 = ATA66
UDMA 3 = ATA44 (very rare, my liteon 16x dvd has it, but it shows up as UDMA0 at startup)
UDMA 2 = ATA33
UDMA 1 (DMA) = ATA16 (not really a proper 'ata' standard.

<b>Paying for Sex didn’t mean you couldn’t get it any other way – it meant that you could afford the convenience option, same as any other service.</b>

 

[goatcheese]

Most BIOS's will show the UDMA mode on boot-up. But once you are within Windows (any version), is it possible to see what DMA or PIO modes your drives are currently using?

All I can find is the DMA enabled checkbox, which just lets you know that "some" DMA mode should be in use... not too helpful!

 

[lhgpoobaa]

If its just win9X/ME, then you are basically limited to a DMA check box.
If you are using win2k/XP then it will say UMDA for ata33/44/66/100/133 or DMA for low end drives that are just ata ~ 16mb/sec transfer rates. Still not entiry helpful.

If the drive is on a 80wire IDE cable then it should default to the fastest ata mode supported by either the drive or controller (whichever is lower).

If you wish to find out exactly what it is, i believe (though im not certain) that SiSoft Sandra will tell you the exact UDMA mode.

<b>Paying for Sex didn’t mean you couldn’t get it any other way – it meant that you could afford the convenience option, same as any other service.</b>

 

[Teq]

Actually win2k just says "UDMA Mode" without giving you the number.
(A source of constant frustration to me, I might add.)


--->It ain't better if it don't work<---

 

[lhgpoobaa]

yes i said that. UDMA for ata33 and above, DMA for ata (ata16) and pio for anything below.
Try sandra anyone?

<b>Paying for Sex didn’t mean you couldn’t get it any other way – it meant that you could afford the convenience option, same as any other service.</b>

 

[goatcheese]

It's the "should" part that is the problem. You are right, it "should" default to the fastest ATA mode. But it would be so useful to see what it is REALLY doing. Especially since MS's new O/S's will actually DROP your DMA/PIO level down if it encounters errors (without telling you, naturally). As I see it, that could mean a simple cable problem (which is later corrected) could mean that your computer is running in a slower mode because Windows automatically degraded the transfer mode when the cabling problem existed.