Assuming I have a SATA III SSD drive that has a throughput of >500 MB/s. What is a reasonable estimate of the effective throughput on a SATA II controller?
I know that SATA II has 3.0 GBit/s theoretical throughput but I am looking for a value of the effective throughput.
3 Answers
I have a SATA II motherboard and a SATA III Crucial M4 SSD that can read above 400MB/s. With the AS SSD benchmark tool I get 265MB/sec read rate, indicating my maximum SATA 2 throughput.
I should point out that the main benefit of a SSD is not maximum transfer rate, but low latency and fast random access. You still get all those benefits on SATA 2, so it's well worth it.
To cover a real-world file transfer scenario unrestricted by drive performance, I copied a 8GB file from a SSD to another SSD with TeraCopy. It yielded an average speed of 141MB/s, indicating a total of around 280MB/s throughput.
A little bellow 300MB/s. You can read more here: Also:
"Second generation SATA interfaces run with a native transfer rate of 3.0 Gbit/s, and taking 8b/10b encoding into account, the maximum uncoded transfer rate is 2.4 Gbit/s (300 MB/s)."
If you put that SSD on SATA II you should expect +/- 300MB/s.
1I'd have to say it depends on the drive (rpm, cache, etc..), also the OS, are you referring to read or write, to/from what type of device, all this factors in. In the real world I have seen sata-to-sata copying of 50-60MB/s, which equates to .39-.46 GBit/s, so a little over 10% of theoretical throughput. I wasn't complaining, this was a windows machine w/ 4GB ram, and this was sustained for at least a couple of minutes.
3
