Interpretation of the cracking speed

Hi all,

I have used hashcat for a few times. Now I am thinking of buying a video card to try ocl-hashcat to see if it is better. To compare them, especially in terms of speed, I am quite confused. I see several description of speed:

1. on the website, "Performance" section with the speed example of tested computer, it says "xxM c/s"

2. in hashcat output shows "Speed/Sec: xxM plains, yy words"

3. in ocl-hashcat output shows "Speed GPU #1....xx kH/s"

so, what does each mean, and are they comparable?

searched for a while but found no relevant posts.

thanks!