It would still be an upgrade. What matters more is the IPC (Instructions Per Cycle), which Ryzen has at least 52% more than previous AMD processors. So if they were the same clock rate with the same number of cores and threads, the Ryzen would still be 52% faster.
Some games prefer higher single-core speed while other games prefer more cores. Either way the Ryzen 7 1700 will be faster than your FX-4300 in every respect.
Not only does the Ryzen 7 1700 have 8 cores, it has 2 processing threads per core (simultaneous multithreading). So it has 16 processing threads compared to your FX-4300's 4 processing threads.