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Thread ID: 143082 2016-11-17 07:23:00 SSD drives vs SATA3 bottleneck? Nomad (952) Press F1
Post ID Timestamp Content User
1428850 2016-11-17 07:23:00 Just a curious question. I have a Samsung EVO 850 (non pro) but looking at the pro they do read / write speed up to 500MB/sec which is ~4,000Mb/sec (small b). SATA 3 is 6Gb/sec right. How does one saturate it, the internet says about this.


Cheers.
Nomad (952)
1428851 2016-11-18 01:48:00 "Up to".
I have the same, doesn't quite get that sort of performance.
Chilling_Silence (9)
1428852 2016-11-18 04:00:00 Some SATA drives claim up to around 550MB read speeds, which allowing for overheads is probably pretty close to maxing out the interface. 6Gb/sec isn't possible in practice either I believe. AHCI adds some overhead and inefficiencies.
One problem is when interface speeds are specified they are talking about the theoretical maximum of the connection including all overheads, error correction, etc. Actual data throughput always maxes out at a lower number. This is true for SATA, PATA, USB 1,2,3, Firewire, etc, nothing hits the maximum stated speeds, ever.

The PCIE based NVME drives starting to become more common however currently claim up to 3200MB/sec showing what's possible with more bandwidth and a more efficient interface (over AHCI which wasn't designed for SSDs)
www.cnet.com There's your evidence of the SATA 3 interface bottlenecking SSD performance.

But all that speed costs a fortune and most home users wouldn't really notice it enough to justify the money.
dugimodo (138)
1428853 2016-11-18 19:33:00 Actually that's a good point, ensure that you're set in your BIOS as AHCI, and not IDE emulation.... Slows it down a lot if you're emulating IDE. Chilling_Silence (9)
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