Bar graph performance


I am new to matplotlib. So if I ask sth stupid, please bear with me.

I am using matplotlib to present large data set in different graph types,
bar, dot, line, etc. I find that the bar graph has very bad performance.
Say, I draw data points of about ten thousand. Using dot graph, it draws
in a second. But using bar graph, it draws in tens of seconds.

I was wondering what causes this difference. Is there a way to improve the
bar graph performace? (Maybe I am not drawing it right, then, please give
me a pointer)

Below is a simple example:

from np.random import uniform
from numpy.random import uniform
x = uniform(0, 10, 14000)
y = uniform(0, 100, 14000)
plt.plot(x, y, 'bo'), y)