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I bought a new SSD, the Crucial 128GB m4. According to AS SSD Benchmark it can have 415 MB/s read and about 175 MB/s write.

I have an Asrock X58 Extreme Mainboard with 6 onboard SATAII connectors. So I thought I need a SATAIII Controller, so I bought and Asrock SATAIII PCIe Controller.

Now the speed on the SATAIII is much too slow, 150 MB/s read, 105 MB/s write. I've installed the latest drivers from Asrock.

When I plug the SSD into the on board SATAII Controller I have 360 MB/s read and 175 MB/s write speed.

What is wrong with it? Why is it not performing as it should?

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What speed is the PCIe slot you've plugged into? – user3463 Sep 4 '11 at 23:15
It's an Asrock X58 Extreme, in the specs it says "PCI Express x1" – JohnnyFromBF Sep 5 '11 at 7:43
up vote 1 down vote accepted

My guess is that your PCI Express slot is the bottleneck, especially if it's a x1, which means one lane. Your newer slots have 16 lanes, and I'll bet that on those faster slots, the drive would work faster too.

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I plugged it into the x16 one, but it was still slower than the native SATAII Controller, pretty frustrating those slow Intel PCIe lanes. – JohnnyFromBF Sep 8 '11 at 14:47
It's an x1 card. – David Schwartz Feb 29 at 0:17

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