I don't think he's referring to a "bottleneck" in the usual sense (IE the CPU is too slow the let the GPU fully be utilized, GPU is too slow so the CPU is wasting cycles, etc).
Instead, since the PS4 uses an APU, the CPU and GPU are on the same die. That is MUCH more efficient for communication between the two, compared to a PC architecture, which are just separate, standalone parts that are limited by the motherboard in how fast they can communicate with one another.
Obviously the sheer power of PC gear overcomes these limitations, but compared to previous console architectures, the PS4 looks like it would have considerably less bottlenecks.