IPS delay with 8000 signatures vs. 20 signatures

Hello I have a question about IPS delay. we have a 600D Fortigate. I want to know that is there any difference from delay's perspective for an access rule with an IPS enabled by  an 8000 signatures-profile  and a 20 signature-profile. It's good to know that I have more than 50 access rules with IPS enabled.

Thanks