SATA 3 PCIe Controller working with decreased performance (slower than SATA 2)

After reading this question about maxing out an SSD I decided to do so myself.

My mobo only supports SATA 2 and has two PCIe 2.0 x1 connectors (which promiss up to 500 mb/s). So after some searching I decided to go with this controller from amazon.

My Samsung magician benchmark before upgrade (running SATA 2):

enter image description here

Now after installing the controller all of the benchmark scores are lower (even though the Samsung Magician app confirms its connected to a SATA 3 port):

enter image description here

What can I do to remedy this? Any help is appreciated.

V M

Posted 2014-06-09T08:43:02.180

Reputation: 145

The controller you bought doesn't promise 600 MB/sec transfer rates it promises transfers rates up to that. I quote "transfer rate up of 600 MB" there is a huge difference. How many times did you run this test? Have you made sure your using the current firmware? – Ramhound – 2014-06-09T10:57:50.377

I've ran the test twice, both tests yielded similar results. I am using the current firmware. – V M – 2014-06-09T12:53:38.810

Answers

The SATA ports on your motherboard are wired into a PCIe 2.0 lane, which allows up to 500 MB/sec (which is shared among all six of its SATA 2 ports).

In looking at the specs for that card, I found the following:

Compliant with PCI Express Specification 1.0a. Design for PCIE 1x

The PCIe 1.0 spec only allowed for 250 MB/sec per lane. Minus the 20% protocol overhead, you're looking at only ~200 MB/Sec. Your SSD is pegging that card to its limits.

Basically, the card you bought is a cheap no-name card whose advertised specs are misleading. Even though the SATA 3 controller is faster than the one on your mobo, they wired it to a bridge chip that is far slower and then advertised a spec that the card cannot physically achieve.

Wes Sayeed

Posted 2014-06-09T08:43:02.180

Reputation: 12 024