It seems like there might be some confusion in the question. The options provided (3 GHz, 1 GHz, 2 GHz, 4 GHz) refer to processor speeds, not disk space.
To determine the minimum disk space needed to install Photoshop, you typically need to refer to Adobe's official system requirements, which usually specify a certain amount of disk space (in GB, not GHz).
As of my last knowledge update, Photoshop generally requires around 10-15 GB of available hard drive space for installation, but this could vary based on the specific version and any additional resources needed for projects.
If you are looking for a specific answer regarding disk space requirements, please look up the most recent Adobe Photoshop requirements for the version you want to install.