Does the "f" variant have the ability to limit the clock speed to a number you want? Are you able to modify the "v/f offset" values with a + or - sign? I only have the K so I don't know if these are K specific options but if also available to you, this is where you undervolt. With the 11700K, you're probably best off limiting the max clock to 4600MHz per core and start testing with the - offsets starting at 0.010mv.