It really matters very little that RK3588 has 8 cores, because the Cortex-A55 cores are very weak.
The reason why RK3588 may beat N100 in multi-threaded benchmarks is that the latter has a very low base clock frequency, due to the higher power consumption when all the cores are active. N100 needs a better cooling than RK3588 in order to reach its maximum possible multi-threaded speed. With good enough cooling that will prevent the drop in clock frequency, N100 will beat easily RK3588 in any benchmark, because the Intel Gracemont cores have a speed similar to the Arm Cortex-A78 cores and much greater than the Cortex-A76 cores of RK3588.
It should be noted that Radxa X4, due to the constraints of the credit card size, has only a 32-bit DRAM interface. So its -4800 memory is equivalent with a -2400 memory of the bigger N100 boards, which use a 64-bit DRAM interface. The good RK3588 boards also use a 64-bit DRAM interface (with a somewhat lower speed, e.g. -4267), so they may win in benchmarks that are limited by memory bandwidth.
However in the applications in which I am interested for such a small board like Radxa X4 (like a network router/firewall or a controller for some custom hardware) the performance is almost always limited by the speed of the peripheral interfaces, so Radxa X4 will be better than any existing Arm-based SBC.