Problems Plotting Mp3 Audio Data Using The Mp3 Read Function

I am using MatLab 2012a for the Mac. In order to evaluate my mp3 audio data I downloaded the mp3 read and write from the file exchange. I can read the data in, but when I plot the variable "Y", the computer completely grinds to a holt and then becomes extremely sluggish. So much that you can't do anything with the data except close the figure. I've made sure all the appropriate mp3 encoders are within the directory, etc. I can't seem to find anyone else having the same problem. I have 8gb of ram and a dual core processor.

[Walter Roberson]

After you read the data in, what does size() of the audio data show? And how are you plotting it?

[Darryl]

You have just made me realise that the audio mp3 I was trying to plot was 20 mins, which in size is: 53285760.

[y, sr] = mp3read('Mp3/#02 Test/Cycling Indoors.mp3');
plot(y)

I've just this minute read a 3min mp3 using the same method as above, and its better, but still really sluggish. For example, zooming in, toggling buttons, etc.

I'm going to be working a lot with mp3 so need this to be as snappy as a .wav as I have no problem with them.