SATA II vs SATA III

[Peter.c]

I want to know if there are any different between SATA II and III on NAS? Because my old motherboard only support SATA 3GB/s. And I need the NAS to store the footage as I am editing the video from my computer through gigabit network. 

So, I want to know if there is a huge different between these two.

 

Thanks.

[Mira Yurizaki]

If this is an interaction between your PC and the NAS, the Ethernet line is the bottleneck here (1Gbps vs 3Gbps or 6Gbps either SATA version provides). Especially for hard drives, since they can't saturate SATA 3Gbps yet.

[Bl00dgod]

the theoretical speeds of Sata II and III are 3 or 6 Gbit/s

Serial ATA 3,0 Gbit/s, SATA Revision 2.x    SATA II, SATA-300    2,40Gbit/s  or    300Mbyte/s
Serial ATA 6,0 Gbit/s, SATA Revision 3.x    SATA III, SATA-600    4,80Gbit/s or    600Mbyte/s

depending on your network speed it should be fine  most HDD dont use more than Sata II

practically the last time i checked my speed it was ~90-110Mbit with Sata3 HDD over Gigabit Ethernet

[steffeeh]

And even if you were to get better network speeds in the future, I don't think you will fully utilize even the SATA2 speeds unless you would add in an SSD into the NAS, so don't worry about it.

[knightslugger]

10 minutes ago, steffeeh said:

And even if you were to get better network speeds in the future, I don't think you will fully utilize even the SATA2 speeds unless you would add in an SSD into the NAS, so don't worry about it.

...or several. two in a RAID0 would probably do it, but who in their right mind stores video on a RAID0? Offloads for processing, sure, but store? #ohhellno.

 

@Peter.c typical HDDs in a NAS top out at 1/10th-ish of what your network speed is capable of delivering.

[mariushm]

SATA 2 is 3 gbps

SATA 3 is 6 gbps

 

Data is transferred with 10:8 encoding meaning for every 8 bits of info, 2 extra bits are for error correction and basically reducing risk of data being corrupted.

 

So sata 2 can actually do 3 gbps = 3000 mbps  * ( 8/10) = 2400 mbps. There's 8 bits in a byte, so we have 2400mbps/8 = 300 mBps or 300 million bytes, which you can write as 300 MB/s or (using the old 1024 bytes in a KB notation) : 286 MiB/s

 

sata 3 can basically do double that, so up to 600 MB/s or 572 MiB/s

 

That's the maximum interface speed, mechanical drives generally can barely reach around 260 MB/s and as  the disk heads move towards the end of the drive, the speed will decrease.

RAID schemes can increase the speeds above limitations of single drives.

 

1gbps network means your speed in and out that NAS will be limited to 1gbps or ~ 125 MiB/s

[Peter.c]

@M.Yurizaki @Bl00dgod @steffeeh @knightslugger 

Thanks all of you for answering my question! I th8nk I will build the AS from my old computer parts instead of spending butt-load of money on new hardware.

[Peter.c]

@mariushm that's really thorough! Thanks!