Maxtor DiamondMax Plus 9: wtf is "1.5 Gb/s"?

[DJFuji]

Oops hit the enter button by accident.

200gb Maxtor drive has an icon on top of the drive saying "Serial ATA 1.5Gb/s". Surely that's not 1.5 gigabits per second transfer rate, even burst. IIRC this is a std SATA150 drive. What are they talking about?

 

[acole1]

how did you get that? maybe its a pothead typo meaning 150mb/sec or 1.5ghz/sec

 

[DJFuji]

I've seen it advertised all over the place with the same wording. I dont know what theyre referrring to.

 

[mb]

My guess is it means 1.5 gigabits.

1.5 gigabits would be 1,500,000,000 bits.
1500000000 bits = 187500000 bytes.
187500000 bytes = 178.8 megabytes.

178.8 megabyes per second then would be the max transfer/burst rate, which I guess seems possible.


Using a more direct approach:
1.5 gigabits = 0.1875 gigabytes
0.1875 gigabytes = 192 megabytes.

I don't know why the Google calculator comes up with two different results depending on how you do the conversion. 😕
Oh, I see. 1.5 gigabits = 1,610,612,736 bits

 

[Ronin]

The SATA II drives are advertised the same way:

3Gb/s. As supa said, note the little b, hence bits. That makes all the difference. The advertising is correct, it's just a marketing ploy for perception of those that don't know the difference, but it's still accurate information.

For clarification, a SATA port has max available throughput of 1.5Gb/s, which is why SATA capable drives are advertised as such (even if they never hit that theoretical number).

 

[ViRGE]

Originally posted by: Ronin
The SATA II drives are advertised the same way:

3Gb/s. As supa said, note the little b, hence bits. That makes all the difference. The advertising is correct, it's just a marketing ploy for perception of those that don't know the difference, but it's still accurate information.

For clarification, a SATA port has max available throughput of 1.5Gb/s, which is why SATA capable drives are advertised as such (even if they never hit that theoretical number).

And for those of you converting bits to bytes, don't forget that SATA has an extra 2 bits dedicated to error control and the like, so you actually need 10bits to transfer a byte, puting the max speed in bytes at 150MB/sec. This is part of the reason they advertise in bits, since it's a tricky way to include the overhead.

 

[Some1ne]

What virge said, the capacity of a SATA-I link is 1.5 Gbps, which is 187.5 MB/sec (note the distinction between bits and bytes). Because of the overhead though, it means that the SATA-I drive can only send 150 MB's of "real" data every second, hence SATA150.

 

[DJFuji]

Thanks guys, didn't know about that extra 2 bits there. That clears things up.

Has SATA II/III managed to actually take advantage of this extra bandwdith? Or is it still pretty common knowledge that the "SATA150" is only a marketing ploy since real world performance increases over UDMA133 is still next to nil?