Quickly remove contents from NSArrayController

FROM : Martin Linklater
DATE : Mon Mar 24 15:16:56 2008

HI. I have an NSArrayController which has over 15000 entries. When I 
clear the array using

[itemBrowserArrayCTRL removeObjects:[itemBrowserArrayCTRL 
arrangedObjects]];

it takes a long time... like 10+ seconds on my MacBook Pro.

Is there a quicker way of clearing the contents ?