Are the read/write of SSD real?
Some SSD have a specification of read:550 MB/s and write:520MB/s. Are these speeds theoretical or is that the real speed most of the time when you are reading and copying large files like HD movies.
Yes they are real. In terms of real world performance it may be under that by just a bit. It comes down to compressed data vs incompressed data. And you have to use SATA 3 ports to achieve those speeds.
These are the benchmarks from last year 2011, they don't have a 2012 version yet:
You can take a look at the read and write benchmarks (MB/s).