Hello. I'm from Portugal, if that matters.

So, here's the thing. I have 2 Bitmain S9 miners in my basement. Right now, I can only turn them on at night, mainly due to the heat they make and the noise also.

I have about 3500€ available to spend on a rig. I'm looking at one with 6 RX 580 Sapphire 8GB Nitro and the price is 3500€. I was already told that the RX 580 is only good to mine ETH and that I should move to something else. ATM I'm looking at a 1660 rig with 6 cards, just a bit more expensive at 3700€.

Electricity is free so no worries about that. What I'm concerned is what's going to happen in July and the fact that POW is going to end.

From my calculations, it seems I should hit ROI on the rig in about 7-8 months. Not in time for July.

So, questions... Is this worth? What will miners turn to once POW is over? RavenCoin? Will the profits be about the same, less or more? I know it's always speculation but there should be consensus here about that.

Another thing, I use Nicehash. Using that, should I even be worried? I mean, doesn't NiceHash mine whatever coin is more profitable with the hardware you have?

And last but not least... Do these rigs make a great amount of heat and noise? I don't mind having a fan or two pointed at the rig, but it cannot be as loud as the S9's, otherwise it's not really worth it.

Thanks and sorry for the n00b questions.