SSD sub-performance 150Mb/s vs advertized 545Mb/s

[kitgzz]

I recently built a new desktop. Motherboard can support SATAIII 6Gb/s and I bought a 120Gb WD Green SSD (WDS120G2G0A). This SSD advertises read speed upto 545MB/s, However on HD tune tests, I barely get 150MB/s as average speed.

I am attaching basic and advanced test result here. Can you please let me know what else to look for here?

HD Tune Pro: WDC WDS120G2G0A-00JH30 (#174780444712) Benchmark

Test capacity: full

Read transfer rate
Transfer Rate Minimum : 41.2 MB/s
Transfer Rate Maximum : 337.5 MB/s
Transfer Rate Average : 153.7 MB/s
Access Time : 0.405 ms
Burst Rate : 58.4 MB/s
CPU Usage : 18.2%

HD Tune Pro: WDC WDS120G2G0A-00JH30 (#174780444712) Random Access

Read test

Transfer size operations / sec avg. access time max. access time avg. speed
512 bytes 4219 IOPS 0.237 ms 0.523 ms 2.060 MB/s
4 KB 1451 IOPS 0.689 ms 11.281 ms 5.669 MB/s
64 KB 1704 IOPS 0.586 ms 4.619 ms 106.519 MB/s
1 MB 378 IOPS 2.642 ms 5.264 ms 378.412 MB/s
Random 625 IOPS 1.599 ms 4.329 ms 317.122 MB/s

HD Tune Pro: WDC WDS120G2G0A-00JH30 (#174780444712) Extra Tests

Test capacity: full

Random seek 3905 IOPS 0.256 ms 1.907 MB/s
Random seek 4 KB 1383 IOPS 0.723 ms 5.402 MB/s
Butterfly seek 5478 IOPS 0.183 ms 2.675 MB/s
Random seek / size 64 KB 2959 IOPS 0.338 ms 45.500 MB/s
Random seek / size 8 MB 113 IOPS 8.853 ms 458.031 MB/s
Sequential outer 5466 IOPS 0.183 ms 341.650 MB/s
Sequential middle 2231 IOPS 0.448 ms 139.412 MB/s
Sequential inner 2332 IOPS 0.429 ms 145.763 MB/s
Burst rate 955 IOPS 1.047 ms 59.716 MB/s

 

[USAFRet]

What make/model motherboard is it?

 

[gasaraki]

1. The WD Green SSD is NOT fast
2. Most of the stated speed of SSDs are at high queue depths. At QD1 where most people use their computers are, slower drives can be a lot slower than advertised.