They will take longer to warm up and the center will be hotter than the perimeter. Put it on and let it heat up till the handle is hot, then start cooking. If the handle isn't hot, the pan isn't warmed evenly. I've even warmed my bigger pans in the oven first to get them up pretty evenly, but you'll still want to pay attention and rotate the food in the pan as it cooks too get the best, most even cook. They do work well frying in fat (fried chicken style) as the oil helps even out those temperatures.