hpman820129
asked on
What UDMA should be?
For SATA hard drive (150Mb/s), the system show UDMA 5.
How about a SATA II hard drive(300Mb/s)? Is it UDMA 6?
However, under ATA modet UMDA 5 should be ATA100, UDMA6 should be ATA133.
How about a SATA II hard drive(300Mb/s)? Is it UDMA 6?
However, under ATA modet UMDA 5 should be ATA100, UDMA6 should be ATA133.
jamietoner
Sata doesn't really have a DMA setting. Sata is a different interface from IDE. IDE drive's do have DMA settings and ata-66 is udma5 and ata-100 is udma6. I have never seen a program show a sata drive with a DMA number just sata I and sata II. Are you sure your not looking at an ide optical drive as it would be a UDMA 5 device. What software are you using to view this?
jamietoner => a few corrections:
UDMA-5 is 100mb; udma-6 is 133mb. (66mb is UDMA-4)
Optical devices almost always show as either UDMA-2 (33 mb/s) or UDMA-4 (66mb/s).
hpman820129 ==> SATA drives are often enumerated under the ATA section in device manager (they are, after all, still ATA devices) ... and usually show either mode 5 or mode 6. But they're actually performing at the SATA rate (150 or 300 mb/s). Also, remember that ANY rate of 100mb/s or higher is well above the sustained transfer speed of any modern drive ... so it really makes very little difference in a drive's performance (since a very small percentage of a drive's access is at interface speeds -- only the PC-buffer transfers). Access time and sustained transfer rate are MUCH more important than whether it's ATA-5/6 or SATA-I or II ==> that's why Raptors (which are just SATA-I drives) easily outperform SATA-II drives that rotate slower.
UDMA-5 is 100mb; udma-6 is 133mb. (66mb is UDMA-4)
Optical devices almost always show as either UDMA-2 (33 mb/s) or UDMA-4 (66mb/s).
hpman820129 ==> SATA drives are often enumerated under the ATA section in device manager (they are, after all, still ATA devices) ... and usually show either mode 5 or mode 6. But they're actually performing at the SATA rate (150 or 300 mb/s). Also, remember that ANY rate of 100mb/s or higher is well above the sustained transfer speed of any modern drive ... so it really makes very little difference in a drive's performance (since a very small percentage of a drive's access is at interface speeds -- only the PC-buffer transfers). Access time and sustained transfer rate are MUCH more important than whether it's ATA-5/6 or SATA-I or II ==> that's why Raptors (which are just SATA-I drives) easily outperform SATA-II drives that rotate slower.
ASKER
I am using SATA as IDE mode.
I want to clarify the right specification, not the actual speed.
Do you mean the SATA UDMA 5 or SATA II UDMA6 is meaningless?
It they are wrong, why XP reports them?
I want to clarify the right specification, not the actual speed.
Do you mean the SATA UDMA 5 or SATA II UDMA6 is meaningless?
It they are wrong, why XP reports them?
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