# SATA1 vs SATA2 vs SATA3



## aksthem1

For single configuration hard drives SATA3 is pointless, but for SSDs, the extra bandwidth really helps.

Some hard drives are still able to saturate the SATA1 specifications.


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## sherlock

Quote:


> Originally Posted by *newn*
> 
> What is the real-world difference between those? The 1.5-6Gb/s doesn't mean anything to me.


Gb/s reads *Gigabits* per second, to covert that to *Gigabyte* (GB) per second you have to divide by 8.

So

SATA I 1.5 Gb/s = 0.1875 GB/s= *187.5 MB/s*

STAT II 3.0 Gb/s = 0.375 GB/s = *375MB/s*

STAT III 6.0 Gb/s = 0.75 GB/s= *750 MB/s*

HDD max read speed is < 200 MB/s (write would be even slower)

new SSD read/write <= 550 MB/s

So SATA II would be plenty for HDDs and SATA II SSD(old ones, write speed < 300), you only need SATA III for new SATAIII SSDs


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## DuckieHo

Real-world consumer difference is actually little.... except when someone is doing file transfers. Most operations are random access.

With HDDs, there is no real difference between SATA 3Gbps and 6Gbps because they cannot come close to staturation.

(Note there are technical differences other than just throughput like NCQ and power management but these generally have little impact on most people.)
Quote:


> Originally Posted by *sherlock*
> 
> Gb/s reads *Gigabits* per second, to covert that to *Gigabyte* (GB) per second you have to divide by 8.
> So
> SATA I 1.5 Gb/s = 0.1875 GB/s= *187.5 MB/s*
> STAT II 3.0 Gb/s = 0.375 GB/s = *375MB/s*
> STAT III 6.0 Gb/s = 0.75 GB/s= *750 MB/s*
> HDD max read speed is <= 200 MB/s (write would be even slower)
> new SSD read/write <= 550 MB/s
> So SATA II would be plenty for HDDs and SATA II SSD(old ones, write speed < 300), you only need SATA III for new SATAIII SSDs


You forgot to account for 8b/10b encoding.

SATA 1.5Gbps = 150MB/s
SATA 3Gbps = 300MB/s
SATA 6Gbps = 600MB/s

Plus there is some protocol overhead as well.


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## appleg33k85

Depends on what you're using (i.e. HDD or SSD, or DVD (optical drive)) - if you're using an optical drive or regular HDD, you're not going to be all that limited on speeds, SATA 2 3Gb/s is good up to ~ 290mb/s read and write vs. 6Gb/s is good up to ~ 600mb/s read / write (which is all not including RAID)

Conventional HDD's do up to ~ 150mb/s on the fastest ones, so you would be fine if you had a SATA I, a SSD would be severely limited.


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## beers

SATA II also brought in a few things such as NCQ.


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## newn

So basically if I am not going for an SSD, you're even alright with SATA1? To play games, watch movies, play music, record videos, do video encoding, image editing, etc.?

beers are the new things useful not in server machines, for use like I've just mentioned, no raids, no SSDs, etc.?


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## Vagrant Storm

Honestly you are fine no mater what you use. For example, If you are gaming you will never be reading more than 150MB a second for a prolonged period of time...

Real world, you won't see a difference between SATA 2 and 3...on SATA 1 you might notice slower boot times and load times if you really looked for it. The benefits of better SATA are really meant for the server arena, but it isn't like they hurt the general end user either. I am sure there will brief instances where it helps, but nothing you can really document...not including benchmarks


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## beers

Quote:


> Originally Posted by *newn*
> 
> So basically if I am not going for an SSD, you're even alright with SATA1? To play games, watch movies, play music, record videos, do video encoding, image editing, etc.? *To use a computer*
> beers are the new things useful not in server machines, for use like I've just mentioned, no raids, no SSDs, etc.?


Fixed. A hard drive doesn't care what kind of data you're storing on it.
It will work and shouldn't present a significant performance loss in a SATA I port.

I have an SSD in my laptop on a SATA 1.5 Gbps port and it's still quite snappy.


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## DuckieHo

Quote:


> Originally Posted by *Vagrant Storm*
> 
> Honestly you are fine no mater what you use. For example, If you are gaming you will never be reading more than 150MB a second for a prolonged period of time...
> Real world, you won't see a difference between SATA 2 and 3...on SATA 1 you might notice slower boot times and load times if you really looked for it.


Just a note... NCQ is not supported on SATA 1.5Gbps. SSDs use NCQ to help increase the number of request and will take a performance hit without it enabled.


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## newn

beers and DukieHo, just to be clear, we're not taking about SSDs here, we are talking about the old-school mechanical hard drives - HDDs.


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## beers

Quote:


> Originally Posted by *newn*
> 
> beers and DukieHo, just to be clear, we're not taking about SSDs here, we are talking about the old-school mechanical hard drives - HDDs.


Correct. I was highlighting it would not be a noticeable difference.


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## DuckieHo

Quote:


> Originally Posted by *newn*
> 
> beers and DukieHo, just to be clear, we're not taking about SSDs here, we are talking about the old-school mechanical hard drives - HDDs.


Already noted above...

Besides, you asked for the differences.... We explained the differences and how the difference affect HDDs and SSDs...


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## FlawleZ

LoL you guys think SSDs are severely limited on SATA I...try SSD over PATA.







I've got a half decent older Acer laptop that's a Turion X2 and 4GB DDR2 yet somehow crippled with only a PATA interface. With my Kingspec SSD I can max the PATA interface at 75 MB/s.


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## FlawleZ

Double post fail


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## DuckieHo

Quote:


> Originally Posted by *FlawleZ*
> 
> LoL you guys think SSDs are severely limited on SATA I...try SSD over PATA.
> 
> 
> 
> 
> 
> 
> 
> I've got a half decent older Acer laptop that's a Turion X2 and 4GB DDR2 yet somehow crippled with only a PATA interface. With my Kingspec SSD I can max the PATA interface at 75 MB/s.


That's because the SSD itself sucked. That PATA controller is probably capable of 133MB/s.

Besides, sequential doesn't really matter that much.... SSDs boost sequential performance by 2-5 times but boost random by 20-100 times. Since over 90% of disk access is random...


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## FlawleZ

Quote:


> Originally Posted by *DuckieHo*
> 
> That's because the SSD itself sucked. That PATA controller is probably capable of 133MB/s.
> Besides, sequential doesn't really matter that much.... SSDs boost sequential performance by 2-5 times but boost random by 20-100 times. Since over 90% of disk access is random...


Of course that's why I bought it at the time the disk access times alone made it 100 times faster. And actually no, the SSD wasn't near its limit. PATA has a bandwidth maximum of 133MB/s yes, but this is bidirectional bandwidth. The interface becomes saturated at far less speeds, near half in fact. The same ssd was also tested in SATA form and averaged 135+/- MB/s.


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## DuckieHo

Quote:


> Originally Posted by *FlawleZ*
> 
> Of course that's why I bought it at the time the disk access times alone made it 100 times faster. And actually no, the SSD wasn't near its limit. PATA has a bandwidth maximum of 133MB/s yes, but this is bidirectional bandwidth. The interface becomes saturated at far less speeds, near half in fact. The same ssd was also tested in SATA form and averaged 135+/- MB/s.


Yes, PATA is half-duplex but you still should have been able to max out a read or write higher than 75MB/s (assuming there wasn't another system or bus bottleneck).


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