Powder detergents generally have a base of washing soda (sodium carbonate), which is a water softener and laundry booster. For water hardness up to 120ppm, a powder detergent will work well to soften the water and clean laundry.
As a result when powder detergents are used in soft water, they can create excess suds. Detergent manufactures have combined their powder detergents so that they can be used in both front and top loaders, by increasing the amount of anti foam in the detergent, to prevent excess suds from occurring in front loaders.
Excess suds are not an issue in a top loader machine, but are in a front loader machine. Excess suds create a cushioning effect, which prevent laundry from being washed properly.
If the combined front/top loader powders are creating suds issues, even with correct laundry loading, try a liquid instead.
For more information on what is in detergents and the function of the raw materials see the Mainstream Detergents, Fragrance in Detergent, Enzymes, Optical Brighteners, Plant based, Sensitive & ‘Eco’ Detergents pages and The Wash Wise Detergent Ingredients Info Sheet.