The gain from HDD to SSD is huge (tested personnaly).Yeah I'm not saying state of the art or anything. But that guy's overall pitch is that the 'quicker' your RAM and SSD, the better off you'll be for performance etc (particularly in cityscapes). As much as that guy's analysis suggests it'll be bottlenecked a lot of the time, it seems like there's still a greater performance gain to be had from higher end CPUs (compared to GPUs).
The gain for quicker RAM or SSD is negligeable (tested personnaly).
So no need for the best ram or best SSD.
The gain from 16Go to 24Go is important (tested personnaly).
The gain from 24Go to 32Go is light (tested personnaly)
About higher end CPUs, the only point important for now (before Vulkan implementation) is the power of one core and not the number of cores. The main thread and the render thread are constrained to one core each, so the real deal is the performance of each cores individualy. Some I5 have better FPS in SC than some i9.