Prepare a large water bath for the sous vide. Attach sous vide machine and set temperature to 131 F (or see post above for temperature suggestions)
Once water comes to temperature, prepare your steak by seasoning generously on each side with salt, pepper and garlic powder. Place each steak in a separate freezer bags or sturdy ziploc bags, or vacuum sealer bags and tightly close. See post above for methods on how to avoid air getting trapped in the bags. Place steak bags in the water, and cook for 2 hours.
Once cooking time is over, thoroughly pat the steaks dry with paper towels. Heat a heavy bottomed skillet over medium high heat. Once very hot, place the steak onto the skillet. Cook for 1 minute until golden brown and seared, then flip to the next side. Add the butter, herbs, and garlic to the skillet and cook the second side for about a minute or until golden brown and seared. Spoon the butter on top of the steak and transfer to a cutting board.
Rest for five minutes or so, then slice if desired.
Notes
See post for information on cooking times depending on doneness of steak, and how to properly seal the sous vide bags.