What is the significance of this short vertical line?
The vertical line of Thermal Paste would spread out in an oval shape giving you better coverage to the rectangular arrangement of the CPU Cores.
This is why it is recommended to apply the Thermal Paste in a short vertical line as opposed to a central pea sized dot for this specific Intel CPU.
On the other hand, if your CPU Cores were arranged in a square, you would use a central dot which would spread into a circle.
The choice between the line method vs. the dot method depends on the geometry of the CPU Cores.
