It is very fast.
Here are the Benchmarks. HD Tune PRO 3.00
read transfer rate
Maximum 108.4 MB/sec
Minimum 51.1 MB/sec
Average 87.6 MB/sec
Access time 12.5ms
Burst rate 90.2 MB/sec
CPU usage 9.5%
After partitioning it in windows there will be 595GB left of the original 640gb.
It is near silent and cool running.