Photoshop cares about memory a lot more than CPU speed so your experience with it will depend on how much memory you PC comes with. Most PC's are still being sold with 512MB.. for Photoshop use.. I recommend nothing less than 1GB. You can purchase add'l memory for about $60 per 512MB.. easily installed as well.

The load time of photoshop will also depend on how many plugins, fonts and action scripts you have. The more of these loaded.. the longer it takes. I recommend only activating those fonts that you need to use during a given session.. use software such as font reserve that allows you to activate/deactivate fonts.. your software will load MUCH faster if you don't have 2000 fonts loaded all the time! Good luck!