I found a guy selling a rx 570 and a 580, and the 580 is $30 dollars more expensive. Should I spend the extra $30 and go for the 580?
Yes. RX 580 is well worth the $30 over RX 570 for gaming.
Depends on the models if the same or both aftermarket go with the 580.
If the 580 is reference but the 570 isn't go with the 570 its still enough to max out most games at 1080p for 60fps gameplay so there is no visual difference between them and will run cooler and quieter. Similarly if the 580 is aftermarket and the 570 is reference avoid the reference.
If both are reference designs I would opt for the 570 its less held back by the poor cooler design.
Its backwards from what most will say but with both being able to cap most titles at 1080p/60fps and both able to run 1440p/60fps with reduced settings there really isn't a visual difference and no real gains from going with the 580 over the 570 for most users.
So best at that point to go with the better cooled or quieter card unless they are the same.
they are the MSI versions of the card
from what I've heard, gaming X coolers are really good
Just to add on to your question, what is the price of BOTH the 570 and 580? If both of them are at a certain price standpoint, you shouldn’t buy either.
You should go 580 cause it has 8 gb gddr5