Most new computors have far higher processor speed than is needed for what they are lkely to be asked to do, expecially if you aren't into gaming. No harm in having the extra, but the chances are any newish computer is going to have anything you are likely to want.

If you have a squint at the boxes of any software you think you might like to use, such as that photo or audio-editing stuff you mentioned, it should indicate what sort of processor speed and other stuff you are going to need for them. You'll probably find you wouldn't be able to buy a computer that didn't measure up to those requirements, because they've phased them out.