Shark complains about a big performance hit with this line, which takes like 80% of CPU time. I have a counter that is updated very frequently and performance seriously sucks.

It's an custom UILabel subclass with -drawRect: implemented. Every time the counter value changes, this is used to draw the new text:

[self.text drawInRect:textRect withFont:correctedFont lineBreakMode:self.lineBreakMode alignment:self.textAlignment];

When I comment this line out, performance rocks. Its smooth and fast. So Shark isn't wrong about this. But what could I do to improve this? Maybe go a level deeper? Does that make any sense?

Probably drawing text is really so incredible heavy...?