> Testing it out with my disk benchmarking script, I got up to 3 GB/sec in sequential reads.
To be sure... is the data compressible, or repeated? I have encountered an SSD that silently performed compression on the data I wrote to it (verified by counting its stats on blocks written). I don't know if there are SSDs that silently deduplicate the data.
(An obvious solution is to copy data from /dev/urandom. But beware of the CPU cost of /dev/urandom; on a recent machine, it takes 3 seconds to read 1GB from /dev/urandom, so that would be the bottleneck in a write test. But at least for a read test, it doesn't matter how long the data took to write.)