Question Which is the better RX 570 graphics card

[8bitKrusty]

Hey so after i recieved helped online for which graphics card is best for my system, i was told the RX 500 range is pretty good for my budget range which is just below $300 AUD . I found Gigabyte AORUS Radeon RX 570 4gb for $229 AUD and Gigabyte Radeon RX 570 Gaming 8gb for $249 AUD. Im new to the pc world and was seeking help, i already bought all the pc parts excluding the graphics card and was wondering which is ideal for mostly gaming and streaming as a hobby, looking at the names i thought i sounded silly seeing how Gigabyte Radeon RX 570 had 8gb compared to the other 4gb and was a no brain but wanted your help thanks in advance

 

[Dark Lord of Tech]

Gigabyte Radeon RX 570 Gaming 8GB