A 9300 is good for around 2GiB/sec, minimum. If you think you’ll need more throughput than that, and you have enough of the right kind of drives in the right topology to potentially produce more throughput than that, then considering something newer makes sense–although I don’t know if newer models actually support more throughput or not, off the top of my head.
Once you’re chasing that kind of throughput, you start getting bottlenecked by PCIe lanes, so keep an eye on that. No controller can handle more throughput than the PCIe lanes that feed it can, and you can look up the maximum throughput offered per PCIe lane for the PCIe version that your controller and mobo and CPU all support.