If you have skis not suited to speed, you will tend to ski slower, especially in the conditions you describe.
Realskiers.com have mph attached to their speed ratings.
If you get a ski that doesn't mind going fast, you probably will ski a lot faster. Maybe a good idea, maybe not.
Typically skis suited to high speeds are a handicap at low speeds or in tight trees, moguls, and other places that reward an easily bended ski.
My estimates from experience reading reviews and skiing
I would say generally speaking slow speed = too slow for most people. About 15 mph speed limit
Medium speeds good enough for you if you are within the middle third of the people on the hill, and you can endure it a higher speeds for short times depending on conditions, but might get yourself in trouble. About 40-45 mph speed limit
High speeds = top 5% of skiers (in terms of speed) About 50 mph speed limit.
Very high speeds > 60 mph speed limit Typically at great cost when skiing moguls trees etc.
Some skis have a range of speeds that includes all of the above.