Big bore vs small bore shocks

[stuey]

Hi everyone. I have searched for this but not found anything so please bear with me!
As an old racer from the 90's where lasting the race was one of the biggest problems (thanks god for brushless and Lipo!), I am not right up there with current thinking. I was wondering what advantages big bore shocks have over the older small bore ones I am used to?
Cheers