hard drive confusion

2 replies [Last post]
gethinc
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Joined: Sep 3 1999

I've just been browsing this board and I have A general question: How come some folk can get 18-19 MB/s out of a 5,400 rpm drive and others 17 out of a 7,200 rpm (that, according to worldspam is 20-30% faster). And then there was AWallace, who could only get 12MB/s out of a new 5,400 ata66 drive, even after running the correction prog from Maxtor? (But 17 out of an older, 7,200 rpm maxtor). Is it to do with other ide devices running - I have 2 ide cd drives and hods of cards in my all purpose PC. Should I be worried?

Geth.

Johnc
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Joined: May 25 1999

Hi.
I suspect a little of the difference between various HD speed measurements is the tool used to measure them. For instance, I have a Maxtor 17.3 Gb UDMA HD which, if I remember correctly, CV mag measured on a Miro utility and got around 14 Mbs. I measured mine on a Matrox utility and got 9.5 Mbs. Innaccuracy is a known factor with these tools.
The main thing is, they are fast enough for consumer video purposes.

Alan Roberts at work
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Joined: May 6 1999

The reason why the apparently slow (5400rpm) IBM drives work wo well is that they use very recent technology. The heads are Giant Magneto Resistive technology (look at IBM's web pages for details) and so they get great bit-packing density than older technolgies. Thus, they get higher bit-rates on/off the disc at lower spin speeds.

The simple rpm figures aren't a reliable indication of performance. My quoting of 18.5 to 19 MB/s comes from the report that MotoDV gives me after capturing DV. The drive doesn't drop frames and runs cool and quiet.