5th generation
By most definitions, first generation computers were the ones built with vacuum tubes.
The first minicomputers were second generation computers, but the most well known minicomputers were third generation computers.
The new iPad (3rd generation) is available in most countries today.
That is most commonly identified as the 3rd generation.
Today.
many people many people
Discrete components. Most components were the same as in first generation computers, but vacuum tubes were replaced with transistors. Operating voltages were correspondingly reduced and circuits sped up as a result.
cache
CMOS memory
Microsoft
The fastest computers are constantly changing. Even if I knew the answer right now, I would be wrong next week. Most the fastest computers today are designed for high performance gaming from companies such as Alienware.
The most common port on new computers today is the USB port. USB is highly popular because of high data rates and its plug and play ability.