I think the most ideal thing to do with differs on your budget.
If you have a budget
- Buy a new card
- If you have the luxury of time and not rushing it, wait for the new RX 5500 or any other new series
If you don't and decide to buy a second hand
- Make sure that you buy a GPU that hasn't been used for mining (yet)
- Do a stress test before buying the said GPU
If you are assembling a new mining rig, then I'll suggest going for second-hand RX580s and similar series GPUs.
You'll be able to get them for very cheap. I've seen ~$75 - $100 for the price of one.
It could give you the most bang for the buck for your money but I don't agree that having a second hand would be the most ideal one for setting up a new mining rig. The most common thing is that if you buy a second hand, it could have been used previously from mining and you wouldn't want that. The strenuous amount of power that has flown could have damaged and input high heat towards the actual device. I doubt somebody would want to use it again, and it might not give you the optimum performance too.
If you are assembling a new mining rig, then I'll suggest going for second-hand RX580s and similar series GPUs.
You'll be able to get them for very cheap. I've seen ~$75 - $100 for the price of one.
Optimize them and you can easily get around 30 MH/s per card.
At the moment, it's not worth to spend much on new GPUs just to mine.
If you are purchasing it for yourself and going to do different tasks with the GPU other then mining.
Then go with 1660ti SUPER as it will be much better overall.
1660ti will support tons of different algorithms to mine.
Moreover, miners for RX5700 is not even optimized.
Thanks for the reply, I have many rigs of 470/570/580, I wanted to try something new. more eficient and powerful, but if you say that the new NAVI architecture is not optimized I will wait.