SATA II vs SATA III (SSD speeds)

[lxMaDnEsSxl]

In real world tests, is there any big differences between running a decent SSD today at 3Gb/s vs 6gb/s, or are the differences in most cases negligible?

 

For example, boot times. Would they be nearly the same?

And in what instances would SATA III destroy running an SSD in SATA II?

 

Yes, I do know that SATA II just limits the speed to 3Gb/s, but can I get some examples or numbers of real world tests on how performance would be impacted?

 

Thanks.

[Assassin]

In real world tests, is there any big differences between running a decent SSD today at 3Gb/s vs 6gb/s, or are the differences in most cases negligible?

 

For example, boot times. Would they be nearly the same?

And in what instances would SATA III destroy running an SSD in SATA II?

 

Yes, I do know that SATA II just limits the speed to 3Gb/s, but can I get some examples or numbers of real world tests on how performance would be impacted?

 

Thanks.

Tom's Hardware has an excellent article on this. 

http://www.tomshardware.com/reviews/sata-6gbps-performance-sata-3gbps,3110.html

 

[lxMaDnEsSxl]

Tom's Hardware has an excellent article on this. 

http://www.tomshardware.com/reviews/sata-6gbps-performance-sata-3gbps,3110.html

 

How come with file copying there is barely any difference, I thought that SATA III would make it faster because of faster reads and writes = faster copying?

 

And in what cases would SATA III be substantially greater in performance?

[alpenwasser]

How come with file copying there is barely any difference, I thought that SATA III would make it faster because of faster reads and writes = faster copying?

 

And in what cases would SATA III be substantially greater in performance?

If you have large sequential reads and writes, SATA III will be

faster, but since most real-world usage will be random file

operations, and those operations are significantly slower, the

different between SATA III and SATA II in practice is not that

significant.

This is also the reason why faster SATA interfaces such as SATA

Express are largely pointless for now, only in very few scenarios

will you see any actual benefit from those. To really take advantage

of high interface speeds in daily usage scenarios, SSDs would

need to be significantly faster for random I/O, which I personally

doubt will happen any time soon TBH since it would make them

quite a bit more expensive (you'd need faster flash, faster

controller chips, and so on).

[lxMaDnEsSxl]

If you have large sequential reads and writes, SATA III will be

faster, but since most real-world usage will be random file

operations, and those operations are significantly slower, the

different between SATA III and SATA II in practice is not that

significant.

This is also the reason why faster SATA interfaces such as SATA

Express are largely pointless for now, only in very few scenarios

will you see any actual benefit from those. To really take advantage

of high interface speeds in daily usage scenarios, SSDs would

need to be significantly faster for random I/O, which I personally

doubt will happen any time soon TBH since it would make them

quite a bit more expensive (you'd need faster flash, faster

controller chips, and so on).

 

How much of an improvement would I see with today's SSDs if I run it on SATA II vs my HDD @5400rpms, specifically with sequential reads/writes?

I've read that "As a rule of thumb approximately 50% of a typical users disk access on a PC will consist of sequential reads and writes.".

[alpenwasser]

How much of an improvement would I see with today's SSDs if I run it on SATA II vs my HDD @5400rpms, specifically with sequential reads/writes?

For sequential speeds, if you have a fast enough SSD, it should be

able to saturate a SATA II link.

In general though, what makes the user experience with an SSD so

nice are not the sequential read/write speeds, but the vastly

reduced access times compared to an HDD, that's what gives a system

residing on an SSD its snappiness.

As an example: My server's OS resides on an Intel 520 SSD

(120 GB version), but is hooked up to a SATA II link. I don't

really feel any difference in daily usage between that system

and and the machines in our households which have their OSs

reside on an SSD hooked up to a SATA III link. Yes, I know

it's not a very scientific test, but in the end what matters

most (IMHO) is how snappy a system feels to you when you use

it.

I've read that "As a rule of thumb approximately 50% of a typical users disk access on a PC will consist of sequential reads and writes.".

I'm honestly not sure, but that sounds a bit high to me TBH,

but then again, it's not like I have any reliable numbers to

counter.