Common SSD read/write throughput?

What is the common SSD read/write throughput on common SSDs?

Following is a very brief test of the speed of a SSD that I have by hand:

# time dd conv=fsync if=/dev/zero of=./test bs=8192 count=1048576
1048576+0 records in
1048576+0 records out
8589934592 bytes (8.6 GB) copied, 20.6098 s, 417 MB/s

real 0m21.377s
user 0m0.089s
sys 0m5.806s

# sync
# echo 3 > /proc/sys/vm/drop_caches
# time cp ./test /dev/shm/

real 0m24.757s
user 0m0.019s
sys 0m4.295s 

In summary,

Write: 417 MB/s
Read: 347 MB/s