If you look at the part of the article concerning adding discrete graphics you will see a chart listing a G620 alongside the AMD A8-3850. The chart shows increase performance as they increase the power of the graphics card.
If the CPU was not capable of powering the cards there would be no increase and that would for all intents and purposes be what people refer to as a bottleneck.
The 550Ti is shown in the chart and the 620 is getting more FPS than the A8-3850.
The key thing here is that while the CPU is capable of running the card and getting acceptable frame rates, its going to look pretty silly compared to if you was running a CPU like a 2500K or a Phenom II 965.
So the CPU will run the card ok, just not as well as a more powerful CPU ( obvious really) which you will get some people tell you is a bottleneck which it is not. Its a restriction.
Hope that's helpful and not confusing. Any questions please just ask.