I got higher overclocks with the storm before I took my IHS off.

It has to do with the "even" cooling the storm provides. It removes hotspots in the core, to remove stability problems. This usually translates into a higher overclock vs. a non-impingement block anwyay.

On my bare core, I am running my whitewater block. This weekend, I am going to run the storm. We will see if it offers a higher overclock over the WW.