SATA 3 vs. 2 vs. 1 real-life transfer rate differences for mechanical HD's?

[kwo]

So, I started out this morning with what I thought was a simple question:

Are there significant real-life transfer rate differences for mechanical SATA 3(6Gb)/2(3Gb)/1(1.5Gb) hard drives?

I've done a number of google searches and on this forum to see what information exists. Surprisingly, there seems to be a scarcity of information, hence my new post.

From what I can garner, a mechanical hard drive has yet to sustainably saturate the SATA 1 (1.5GB) interface. So, the purported transfer speeds of current mechanical SATA 2/3 hard drives are more for "compatibility" than for actual increases in transfer speeds.

In contrast, it seems that the SATA 2 & 3 specifications are more to pave the way for solid state drives which seems to be the general trend.

So, the upshot: If you have SATA 1 mechanical hard drives that are currently functional and provide sufficient storage for your needs, there is no significant advantage (>10% in my book) to upgrading to SATA 2/3 mechanical hard drives.

Agree or disagree? (& why?)

 

[zod96]

That is exactly what I would like to know as well...

 

[JeffreyLebowski]

Like with most computer hardware, some parts of hardware is upgraded and doesn't give you a huge boost in performance that the specs would indicate. In hard drives, the reason is, the read/writes from the platter can only happen as fast as the platters can spin and the read/write heads can physically move to the data.
Now the through put of SATA 1,2,3 is higher, and bursts of data that are in the drives cache can move quicker for that 1 second, it's just going to backup waiting for the drive to spin somemore to get the data.
With SSD's the newer SATA protocols will become more important as solid state memory is going to be faster than spinning media.
Tom's article on it.
http://www.tomshardware.com/reviews/usb-3.0-sata-6gb,2583.html

 

[Yew]

Remember to separate the fact that SATA is a bus interface and a hard drive is just that - an independent device with its own I/O capabilities. Check the advertised i/o of the ssd and ensure your sata bus interface meets/exceeds it and check how many separate channels connect to the system bus for your system board or card.

Also (just in case this helps) remember that HDDs used to have parallel bus interfaces where 7 or 8 bits were i/o simultaneously, and as such we talked about BYTES per second (8 bits, now) while now we value SATA performance in BITS (still just 1) per second so be sure you do the math correctly as many hard drives are still advertised in bytes per second (just like windows' file transfer counters and misinformed ISP sales reps lol) When reading measurements, check for capital or lower cased letters and know that you can roughly express 6Gbps (bits is lower case b) as 750MB (bytes is upper case B) per second....that is if they are following the rules heh.

Regardless, a faster bus interface speed is always better, because its not just the size of a pipe, it is also a measure of time; how many (milli/micro)seconds do these bits take to reach the SATA bus interface on the other side of that pipe can be calculated by dividing those numbers. Milliseconds are lifetimes inside a PC and your disk is the slowest critical I/O device in your system except maybe your network interfaces.

How much your drive can actually seek/read-write/receive-transmit in a second is a completely different set of measures but make sure you take it into consideration by checking it against the SATA interface speed and ensuring you arent trying to save a buck on the board/sata controller and end up with drives that could have utilized the 6Gbps interface. Some drives are coming out that advertise over 400MB/second so it would be wasteful to not have a SATA 3 bus interface to connect them to!

 

[Insert_Nickname]

So, I started out this morning with what I thought was a simple question:

Are there significant real-life transfer rate differences for mechanical SATA 3(6Gb)/2(3Gb)/1(1.5Gb) hard drives?

I've done a number of google searches and on this forum to see what information exists. Surprisingly, there seems to be a scarcity of information, hence my new post.

From what I can garner, a mechanical hard drive has yet to sustainably saturate the SATA 1 (1.5GB) interface. So, the purported transfer speeds of current mechanical SATA 2/3 hard drives are more for "compatibility" than for actual increases in transfer speeds.

In contrast, it seems that the SATA 2 & 3 specifications are more to pave the way for solid state drives which seems to be the general trend.

So, the upshot: If you have SATA 1 mechanical hard drives that are currently functional and provide sufficient storage for your needs, there is no significant advantage (>10% in my book) to upgrading to SATA 2/3 mechanical hard drives.

Agree or disagree? (& why?)

If it works, use it. It's only the absolute newest drives that are saturating SATA1 (150MB/s in theory, more like 120MB/s in reality. Newer 7200RPM drives can do ~150MB/s sequential) and they are native SATA3. The only benefit is reading from/writing to the drive buffer...

Now if we're talking SSD's it's a whole different story as many controllers can saturate even SATA3.

I'd recommend an SSD, as for access times they simply blow mechanical HDD out of the water (0.01ms SSD vs ~15ms HDD)...

 

[ShintaiDK]

Between SATA2 and SATA6. Nothing. Between SATA1 and SATA2, minimal.

Its more the new commands associated with the new SATA standards than its the bandwodth for HDs.

 

[Coup27]

Between SATA2 and SATA6. Nothing. Between SATA1 and SATA2, minimal.

No offence but you really should standardise on the way you refer to these specifications. SATA1, SATA2 and SATA6 makes no sense as the 6 must mean Gbps (or Gb/s) but by the same system it makes SATA2 is only 2Gb/s which isn't correct. You should really use the correct method of 1.5, 3.0 or 6.0 Gb/s or Gbps.

 

[Erenhardt]

It is not about SATA transfer.

I have raid from 2x SATA2 7200rpm drives with performance worst (70MB/s) than single modern HDD(150MB/s).
2x SATA2=1x SATA3 so why is that?
Old hard drives (SATA1/2) are slower only because of data density on a plate nothing more.
I'm tired of reading HDDs specifications... Transfer rate: 6gbps (600MB/s)... O rly?

 

[BFG10K]

From what I can garner, a mechanical hard drive has yet to sustainably saturate the SATA 1 (1.5GB) interface.

I suppose it depends on your definition of "sustainably".

Newer 1TB/platter 7200RPM drives can easily exceed 150MB/sec (the SATA1 limit) for a significant portion of their area. Here's my 1TB VelociRaptor, a 10,000RPM drive which is the fastest SATA drive you can get:

As you can see, it exceeds 150MB/sec for about 70% of its surface area.