Fastest GUI toolkit?

[Gordon Williams]

I have an application where I need to draw many lines fast and repeatedly
(an oscilloscope).  The number of lines ranges from about 1000 to 16000. 
Currently I have the application using Tkinter but I am finding it too
slow.  I am currently using W95 as an os, but would prefer to make the code
portable across other os if possible.  Right now speed is more important
than portability so I would be willing to give this up.

I would like to draw 1000 lines in 1/10 of a second on a P166 machine.  (Am
I way off the mark??)  I was hoping that someone would have tried different
packages and could give me pointers in the right direction.

Thanks,

Gordon Williams