Hemalurgy and Compounding

[Mati]

So as there is power loss when creating spikes would it still be worth to have compounding? The power increasy normally is be big, but here you would have loss both in feurochemical and allomantic side.

[Pagerunner he/him]

It depends on exactly how Feruchemy from Hemalurgy is inefficient. If it means that you get less out of your metalminds than you put in, then potentially. If it means that you are capped at the speed of storing and tapping, then not so much. I don't know if we've learned specifically how it manifests.

Compounding is applying energy from Allomancy to a Feruchemical usage. You don't need much of a Feruchemical charge to key in the compounding, so as long as you're even getting a little bit of power out of your Allomancy, you should be fine. (i.e., If burning a bead of tin gives you less raw power than you lose by storing in that bead for a few moments, then yes, compounding might not be for you, since your tin is just so darn weak.)

[Weltall]

You mean if you granted yourself the same metal in both powers? Yes, it would still be perfectly viable. Even if your Allomancy and Feruchemy result in a weaker net effect than the original bearers of the abilities, you would still have the ability to exponentially increase your Feruchemical reserves and get all the benefits of that. Assuming sufficient access to the metal you need, the only difference would be how long it takes to build up the same level of reserves.

To illustrate, let's imagine a same-metal Twinborn and someone who got both powers via spikes. Just making up some numbers and using arbitrary units to make the math easy, let's say that the Hemalurgical compounder can store an attribute half as quickly as the Twinborn and when they burn a metalmind they get a fivefold increase instead of a tenfold one. The Twinborn stores for an hour and gets ten 'units' of their trait. The spikee stores for the same time and gets five 'units'. Both then burn the metalmind, resulting in the Twinborn having 100 units and the spikee having 25. If these two were in a race, the one who gets compounding via Hemalurgy will never beat the amount of charge the Twinborn could obtain but just in terms of building up a charge far faster than one could do so normally, the Hemalurgical compounder is still getting a massive benefit from their ability, they just need more metal and more steps than a Twinborn to accumulate the same level of charge.

Now factor in how annoying it is to store something like health or speed and how powerful it is when you can get around much of that restriction and you can see why even a weaker level of compounding is still ridiculously useful.

[Mati]

Also there is question (unless it was asked already) when does power loss happen in case of feurochemy - as storing, taking or maybe both? If both taking half efficiency you would then get 5 'units' stored * 5 allomancy 'bonus' / 2, so yes still more than starting input. But then all depends on how much increase you get when burning metalmind.