s vs shop bought.
Powder vs Fresh
The instructions on packets of garlic powder often talk about using equivalent amounts in place of fresh garlic when cooking. Personally I don't do that. Even when it's pure, I find that the powder doesn't taste exactly the same as fresh garlic. Good garlic powder can be very pleasant - but to me it is a taste of its own. For this reason I prefer to use it as a seasoning ingredient in place of saltorin slow marinades.