Just some general stuff here:
Make sure you aren't loaded down with software running in the background. This can eat up resources.
Did you accidentally underclock your GPU? I know it sounds like a long shot, but anything's possible.
Has this person you know overclocked their GPU? A 970 can generally be overclocked to base 980 clock speeds.
Are you using the exact same resolutions and the exact same in-game settings?
Now, more specific troubleshooting:
Are you reaching high temperatures? (This really shouldn't affect performance)
Are you using in-game V-Sync? Some in-game v-syncs likes to chop down framerates to 30 when the game drops below 60 FPS.
Does the person you know use different NVDIA Control Panel settings? Some of...