I had a general question about streaming videos online; in particular, on YouTube. What really is required to smoothly stream videos at 360p or 480p? Then for that HD goodness, what really allows a computer to smoothly stream 720p and 1080p?
I'm not too sure whether it's to do with the CPU (speed, # cores, cache size), GPU (chipset, VRAM, memory type) or even HDD (IDE vs SATA).
What contributes to the ability to stream regular videos and, furthermore, high-definition videos online?