The difference between SMD3528 with SMD2835 LED bulbs

Other Types of Lights LED Light Bulbs
1

What is the difference between SMD3528 with SMD2835 LED bulbs? to outward seeming, they are almost the same.
Yet i know there does exist difference. and which one is much better and more energy saving?

2

http://www.lightinstar.com/led-packaging/

http://www.cnc-lighting.com/i-Knowledge-363029/Comparison-between-SMD2835-and-SMD3528-LED-Chips-720863.html

3

Nice source of information, I did not know all this, thanks!