Difference in SSD performace between a SATA II and SATA III PC

[cosrocket]

I have a several year old desktop PC with SATA II interface in which I installed a Samsung 850 EVO SSD. It's running well, but I am wondering specifically to the difference between SATA II and SATA III if there would be a small or large difference in performance  with the Samsung SSD.

[neo1911]

Large difference.

On SATA2, your 850 Evo will max out between 250-300 Mbps sequential read and write speeds.

On SATA3, your 850 Evo will max out between 500-520 Mbps.

[n_K]

I've got a SATA II PC with a OCZ Vertex II and a SATA III PC with Sandisk Plus SSD so there's more at play than just the SATA version here, but do I notice a difference? Yes. How big is the difference? Not as big as the difference between mechanical HDD and SSD but there is big difference when writing/reading to the SSD to me.

[+Warwagon MVC]

Correct, sata 2 will obviously will be slower than Sata 3 but going with an SSD from an HDD is still well worth it. I have a lot of machines in my house none of them run HDD's as boot drives.

[shockz]

Just put an SSD into a HP DV6000 w/ 1GB of RAM and a Centrino Duo 2, from around 2007. It's more than capable of getting a few more years out of it. Boots in less than 30 seconds and doens't really lag around for basic operations. Perfect for word processing, e-mail/internet and even netflix.

[ZakO]

Here's my Samsung 840 on SATA2 vs SATA3 for comparison.

SATA2 / SATA3:

Benchmarks show the difference is quite large, it would be even bigger for an 850 because it doesn't have the 250MB/s sequential write limit the 840 has. In real world use I don't notice a whole lot of difference, obviously it depends on your usage though. Either way it's certainly nothing compared to going from HDD -> SDD.

 

 

[MaverickVA]

Truth is neither will reach the max specified speeds. Same thing applies to mechanical IDE and SATA HDD's as well.

[+Warwagon MVC]

Large file transfers will be faster, sure. But over all launch of applications and such ..not so much.

[n_K]

Truth is neither will reach the max specified speeds. Same thing applies to mechanical IDE and SATA HDD's as well.

That's because of the implementation, not because of the SSD, and is the same for any protocol. The protocol has overhead and if you use more than one device there is contention, etc.

[Jason S. Global Moderator]

the vast majority of data I/O on an SSD is the small 4k files. How often is anyone transferring large, sequential files? SATA2 will never saturate a large set of 4k files b/c all SATA SSDs have 4k transfer rates of <100MB/s. that's not even close to saturating the protocol.

point is, in the 'real world' you probably wont noticed much of a difference b/w the 2 protocols.